Dementia reaches the stage where it is too much for one exhausted, frazzled carer to deal with - it requires a whole team of people caring round the clock. Your dad, unfortunately, cannot understand this - he doesnt realise the amount of care that he needs and wants to go back to somewhere that he recognises, feels safe and can leave the confusion behind (whichever home this is).
You havent said how long he has been there, but it usually takes at least a couple of months to settle (often longer), so he may well settle more. Try and leave the anger behind. I have reached carer breakdown over my OH and was suicidal. I had hidden everything from my (adult) children and I think it came as a shock to them. The thing that has really helped is their support. I expect that your mum is feeling really guilty herself and may well have hidden the worst of the problems from you. Please try and be a support to her.
