A 2-year-old boy is getting cancer treatment in Philly. His parents may be deported to Mexico.

Fabian Flores Alameda is not yet 3, too young to comprehend the lethality of the cancer that pummels his small body or the nature of the crisis that confronts his immigrant parents.

He has multiple lesions in his skull. A plaster cast envelops his weakened left leg, which fractured as he played and jumped around his home.

Fabian’s best chance for survival depends on continuing to receive chemotherapy and care at St. Christopher’s Hospital for Children in Philadelphia, according to his doctors.

But now the Trump administration is threatening the toddler’s undocumented mother and father with deportation to Mexico, where they say their child could not get the treatment he needs.

“Living in Mexico will be a death sentence for my child,” said Fabian’s mother, Damaris Alameda Ramos.

They sought a grant of “deferred action,” a temporary bar on deportation that allows migrant families to stay and work in the country while battling serious conditions like leukemia, cerebral palsy, and spina bifida. The Feb. 11 denial by U.S. Citizenship and Immigration Services has devastated the Horsham Township couple, leaving them frightened and emotional.

The Trump administration ended the program in August — telling families they had 33 days to leave — but resumed accepting applications a month later after an outcry from physicians, families, and elected officials. Advocates worried that even with the program technically restored, the administration would simply accept applications and turn them down.

It’s not clear what’s happening nationwide. But two local attorneys said they’ve seen only denials from the USCIS Philadelphia field office.

Conshohocken immigration lawyer Audrey Allen, who represents Fabian’s parents, said all five applications she has filed since September have been denied.

But across the river, at a USCIS office in New Jersey, the two applications she submitted were approved.

“It shows that it’s completely political,” Allen said.

» READ MORE: Immigrant families with severely ill or disabled children now face deportation by Trump administration

Immigration attorney Ricky Palladino said he’s recently received three denials from the Philadelphia office, and in a fourth case the mother of an 8-year-old girl with blood cancer was denied while her father was approved.

Philadelphia USCIS officials declined to discuss the criteria for evaluating deferment requests, or to say how many have been approved or denied since September.

A spokesperson said that counts of deferment decisions are not part of agency record-keeping, so no figures are readily available. The agency gets about 1,000 requests a year, and most of those are denied, the spokesperson said.

Still, the spate of denials “raises questions about whether somebody above the field office, higher up in USCIS, has provided a new directive, or a layer to the processing of these cases,” said Shoba Sivaprasad Wadhia, director of the Center for Immigrants’ Rights Clinic at Penn State Law. “We don’t know the answer to that.”

She’s identified about 30 cases nationwide where decisions have been rendered since September, but said they show no clear trend of denials or approvals. More information is needed to know if the program has truly, fully been reinstated, she said.

“The public understandably wants to know what’s going on with this program,” Wadhia said. “The level of the accountability is higher now.”

USCIS said it does not comment on specific cases, such as that of Fabian’s family.

Technically only Fabian’s parents are at risk, because he and his 6-year-old sister are U.S. citizens by birth. But the couple can’t imagine leaving their stricken son behind — nor taking him to Mexico.

“I know my son would die if we were forced to return to Mexico,” said Fabian’s father, Fabian Flores Aguirre.

His parents say that despite his illness, Fabian is a happy child. During a recent interview the boy playfully crawled in and out of his parents’ laps, snacking on a doughnut that covered his chin with chocolate frosting.

Ramos cares for Fabian full time, managing the appointments, medicines, and blood tests, and Aguirre, who works for a cleaning company, switched to the night shift so he can be home during the day.

Deferment provides no permanent immigration status. But until Trump shuttered the program, Republican and Democratic administrations had for decades commonly granted deferments, recognizing that American medical care was key to saving lives.

» READ MORE: A South Jersey migrant family with a cancer-stricken child can stay in the U.S. for treatment

So far neither Ramos nor Aguirre, both 27, has received a “Notice to Appear,” the charging document that signals the start of deportation proceedings.

Aguirre was barely a teenager when he crossed the southern border into Arizona in September 2007, traveling from Phoenix to Los Angeles to Philadelphia and finally to Queens, N.Y. He said he came to this country because he needed a job to support his parents in Mexico.

In Queens he was arrested for trying to enter a bar while underage.

Last year Aguirre was charged with drunken driving, and entered Accelerated Rehabilitative Disposition, an alternative program that frees court time by moving first-time offenders to treatment. ARD carries no finding of guilt and is not considered a conviction under the Immigration and Nationality Act.

Ramos entered the United States without permission in November 2012, making her way to Denver and then to Philadelphia. She and her siblings needed jobs, she said, so they could send money to pay doctors in Mexico, where her mother was ill with diabetes.

She and Aguirre grew up in the same small town of Chiautzingo, in southeast Mexico. They reconnected in this country, fell in love, and married in 2013.

Last spring the family was playing in the yard, the parents said, when they noticed a small bump on Fabian’s forehead. They thought it was a bug bite. But a week later it was still there, and doctors were puzzled.

Subsequent blood tests, X-rays, and an imaging scan led to Fabian’s April 19 hospitalization at St. Christopher’s.

He was diagnosed with Langerhans cell histiocytosis, known as LCH, which occurs in one of every 200,000 children, usually between ages 1 and 3. Excess immune-system cells build up in the body, and patients can develop masses of tissue in the skull or long bones of the arms and legs, causing pain, swelling, and breaks.

“I never expected this to happen to my son,” Ramos said, adding that she’s grateful he’s “not in pain, even though his skull is fracturing.”

LCH can be diagnosed as “high risk” or “low risk.” Fabian has the high-risk diagnosis, which is more difficult to treat. Side effects can include stunted growth, skeletal defects, trouble hearing, or neurological problems.

With proper care, often including chemotherapy, 80% of high-risk patients can survive, according to St. Jude Children’s Research Hospital in Tennessee.

Fabian’s parents say they can’t get that treatment in Mexico. In large cities there, excellent specialty-trained physicians and well-equipped hospitals serve the wealthy, while others go without. The care in their hometown consists of one doctor at a small clinic.

“It’s just crushing,” Allen said. “These kinds of programs of relief were created for these exact situations.”