My friend's married dad has dementia and tells all our friends in church that I want to have sex with him and that I am moving in with him. Any advice?

I have had Senior Care training but not much with dementia. So I do understand that this is normal. It’s more upsetting to my friend because she thinks that I must be uncomfortable with it. Her dad tells people that I am moving in to one room with him and that his wife will live in another room. He tells everybody it’s all planned out. He also tells everybody that I have told him that I know how to be sexually active with an older man. I am 55 and he is 90. He tells people that I am an expert with sex with an older man and has actually been more explicit about what he says I can do for him. Her dad has also called me more than a dozen times and left messages regarding this matter. I do not answer them and let my friend know every time he calls. He has also approached the pastor of our church in his office and explained to him about how excited he is that I will be moving in at all. Of course the pastor was a little concerned and we have discussed. His daughter has spoke with the pastor as well. Don’t get me wrong, I am uncomfortable, but I can handle them with a total understanding. I’m trying to give advice to my friend. I want her to know that she can come to me anytime and that it is at least good that it is directed towards me. Any advice would be super appreciated!