I think you will find that without a will from your mum, he has to split all the assets equally between you. He sounds like he's hanging in there for all he can get which is not fair to you. Get on the phone to the CAB - you need to find out your entitlements and get someone to act for you. A letter from a solicitor is likely to have far more effect that you just talking to him about it. Get what you deserve, your mum might have wanted him to stay in the house but not for you to end up with hardly anything out of it. Please phone them and go and see them - we can't do anything, you need to put this on a legal footing without any more delay.