EDIT - Apologies, I missed the "in-law" part and assumed it was your farther and that he had re-married.
Hello DILjean, I'm in a similar position although my father has already retired, this was engineered by the directors of the company he had worked for for 30+ years. He now struggles with an insatiable drive to be doing things, but also not having much to do, and not doing what he does do well either. Funny in a way as he has always been chasing perfection.
In my opinion you don't need to have the "I think you have aspergers" conversation at all, it's really not going to change anything at this point in time. Concentrate on dealing with the dementia and helping to make his wife's life easier too, especially if she is to be caring for him. It really does make sense for them to move closer to those who are able to support her and into a smaller property and this is what you need to steer your father towards. Does this mean they will be further away from you? My mother, who has control issues almost to OCD level, no longer has the time or energy to clean the house to her own high standards, it's not a large place and she finds this challenging herself.
A change of residence would be a good time to change routines, for example I have had to fit a key safe at my parents house otherwise my father hides them when he get hold of them, or removes the front door key from the bunch. Obviously I can understand it's upsetting for him and also beyond his comprehension to understand why he is no longer allowed to have a set of keys for himself. If you convince your father to move house then it could be a time for his wife to take control of issues like this.
If you father has a hobby, or other interests, that will be safe for him to continue as the condition progresses, then these should be encouraged as a future past time, replacement for work and general distraction. Try to increase the number of interests he is involved in with physical exercise to be included if at all possible. With my father as an example then trying to get him to do anything new now that the dementia has a significant effect on him is a complete waste of time and can be very frustrating too.
Work with your father to limit the effects of dementia for as long as possible, aspergers is just a part of him. Good luck.
Last edited by neilson_wheels on 09 Apr 2014, 11:56 am, edited 6 times in total.