How do you find a senior community to accept a registered sex offender?

Contact the AFTD, Assoc for FrontoTemporDementia. You can google them. Also there is an ftdsupportforumdot com. The degeneration of the executive functioning of the brain often leads to inappropriate social behavior that never would have occurred before the onset of this disease. The forum has a sub section that deals with sexuality. There is also a section for people with FTD as well as caregivers. It's a terrible disease that causes heartache for all it touches.

He goes to the VA. Call them.

I believe, not sure but believe, that there are support organisations for FTD? Perhaps they might have some recommendations?

Just by the way, don't feel you need to explain why he can't live with you and your husband. You are under no obligation to house anyone; therefore it is important that he is treated as an independent person in any case - after all, what would become of him if you didn't happen to exist? You are doing right by him now, by helping him to find the right accommodation. Nothing to apologise for! Best of luck, and I hope you will find him somewhere safe and comfortable.