Thank you to everyone. I have spoke to my dad today when I went to see him to bring him up to date what has been being said. (I hate this, he deserves peace of mind.)
He asked if the solicitor could be the LPA and executor if I should go before him? I don't know and will phone the solicitor on Monday to find out. I hope so as then we can both trust this set up. Then my sister would only be in the Will and not have the responsibility which she seems not to want anyway as she won't answer the phone to me and has not been in touch with my dad or the solicitor. You would think that she would have acknowledged one of us by now but nothing apart from running to my mother. So no trust there then again. Very silly. She should be loyal to my dad too but she isn't. Neither is my brother. Regardless of my dad walking the streets for work at times, to make sure there was a roof over their heads and food in their belly.
As far as my mother is concerned, my dad said that he wants nothing to do with her now. He said she hasn't been in touch for years so he thinks it strange that she wants to have contact when Wills are mentioned and LPA. He told me to tell her that she hasn't to contact him at all and if she does phone then he will just hang up on her. I am glad. He still went and decorated for her when they had divorced and she was really nasty to him, so he doesn't need this anymore. Also this means that I don't have to visit her until I really have to, not when I have been summoned, like she has done for Thursday this week. I will tell her I am not going, nicely, but tell her.
Hopefully this will settle things down a bit. What will happen in the future, who knows but hopefully it will be ok as both siblings are in his Will, so he has not left them out at all. It's his decision, as it should be, as long as he can be less stressed and prolong the dementia, and keep as healthy as possible for as long as possible that is my wish. I love being with my dad, he is very funny and a very nice man, who I was stopped from having a relationship with when I was younger due to a very controlling and manipulative mother