Hi
My dad also passed away from this dreadful disease in September. I understand completely what your saying about your mum and she is very fortunate to have your support. I am supporting my mum through this also but I suggested she see a grief counsellor which has been beneficial as she can say whatever she wants without upsetting anyone. It does take time - people keep saying this, I think you just learn to deal with it better. I miss my dad so much and the worst part of the illness was watching him get sicker. I keep telling myself he died peacefully and is in a better place without pain.
Take care