a similar situation with my dad. he got remarried at age 88 to a 73 year old. She is not a bad lady, no complaints there, but his motives and actions are nit clear. He has an increasing problem of dementia and is not making good decisions ( about anything) He resented me stating the obvious ( that he needs help) and got this lady to marry him even though she had not spent more than 50 hours in his company. She didn't realize how advanced his dementia was until too late. Now she is pretty much a care giver and it is wearing her down. Meanwhile they have moved away 700 miles from me and he won't talk to me. i've had three short conversations with him since Nov. 2011. I am not DF'd. I hear he has cut me out of his will ( its not the money but the thought of it that bothers me).
In his case it is very much a problem of dementia and paranoia against anyone who states the obvious( that he has dementia).
maybe its off topic , but thats my story