Should prisoners be eligible to receive expensive medical therapies for illness?

In the United States most definitely yes. The 8th amendment to our constitution prohibits cruel and unusual punishment. If we did not afford our prisoners with appropriate medical care then ill persons convicted of minor crimes punishable by a relatively short sentence would undeniably be default sentenced to death. Because of this it's not uncommon for a severely ill convict (after an extensive medical review) to serve his or her sentence in an appropriate facility capable of keeping that convicted heart beating.