He was unemployed by choice, not incompatibility. I know he has written quite a bit of good emacs documentation and elisp code, and just that is worth donating for to me.
I just spoke to Xah on the phone. He does want people to donate to his paypal address. He can transfer it to someone to cash it out if needed. He will be making further updates on his site, probably later today to be clear about that. He will be looking into bitcoin also. So feel free to donate, I think at least his contributions to emacs documentation make it worthwhile.