By all accounts one of the truly good guys and class acts in pop/rock music history. Here's wishing him a full and speedy recovery. I didn't know about his health issues either. I heard him a few months back on-air with Dick Biondi on WLS-FM, and he sounded great. He and Biondi were talking about going out for pasta together the next time they met up.
And as for him being stiffed by oldies radio, I couldn't agree more (he's certainly in regular rotation on my iPod ;D) But I think the protracted legal battles over the original material in the Cameo-Parkway catalogue probably didn't help matters.