She also can't really be left on her own anymore as she keeps falling over, apparently ringing people literally 20 miles away to come and help her up because she can't remember that my sister is in the house, upstairs or in the kitchen.
Its funny you mention the calling thing, as he is going through a phase of ringing people a lot right now, sometimes up to 20 odd times a day, with the same request or topic of conversation.
In my mind, I know its going to get worse. The person I feel most sorry for is my misses Dad. Currently, his Mum has been doing down the dementia road for some while now, and is in a really bad place, and now his brother. I'm not sure i'd be able to deal with that, so its obviously becoming a huge stress on the family. I guess I'm just trying to help out any way I can. Not that there is obviously too much I can help out with in this sort of situation.
I guess the main thing I can do right now, is try and offer to spend some of my free time with him, try and keep him entertained, even if it is just for an hour every other day or so. Try and make his routine less mundane!