Should an author tell fans he's ill?
A close friend is a published author with a new book (fiction) out by the end of July. It was nearly finished (one chapter left) when he began to face serious health issues. As a result of his health issues, he can't focus, is always drained, is having severe vision issues, etc. It is extremely unlikely that he will be able to finish the book on time, and it's bothering him tremendously. He worries about the effect this will have on his fan base (and his livelihood!). He makes a living off his books, but needs the income to keep coming.
I think he should tell his fans that he's struggling with serious health issues and will complete the book as soon as he can, but he's a very private person and currently hasn't told anyone beyond his closest friends and family, including most extended family. Additionally, I think he may believe this will be viewed as a crutch or excuse or simply that the readers won't care and will move on if they think the books are going to stop coming. There's a lot of unknowns with the health issues, but right now we believe his condition will stabilize at some point and he will be able to return to a normal life. It is unlikely to be terminal in the short run, but there is a chance even beyond that that he may not be able to pick up writing again.
So, the question is -- should an author tell his fans about his illness (essentially go public) to explain the missed deadlines or keep it private?