NASHVILLE, TN — Last week Gov. Bill Lee’s administration issued an ultimatum to hundreds of immigrant families in Tennessee: If parents wished to keep their disabled and critically ill children on a last-resort medical program, their personal information would be turned over to a state agency that shares data with Immigration and Customs Enforcement. The notice, targeting immigrant children without permanent legal status, came with a June 30 deadline and no transition plan for young patients who rely on ventilators and feeding tubes, or who are midway through chemotherapy treatment — healthcare that, until now, has been provided through the…