Someone on Reddit seems to think it was part of a larger effort to promote non-Soviet communist thought

https://www.google.nl/amp/s/amp.reddit.com/r/socialism/comments/40tm8b/why_did_the_cia_help_frantz_fanon_come_to_the_us/

But yeah, pretty strange. I don’t think healthcare in the US would have even been that great back then so who knows why he accepted the help instead of just going back to the USSR for treatment.