Mum's wishes

I'm 16 weeks pregnant and have a problem that is breaking up my family and as this is my first pregnancy I don't want this friction as want my family involved. As this is so personal I would appreciate some advice as because of the nature of it I do not want to talk to my friends. Here goes.. Basically my mum and dad were separated for 12 years and he left her and moved in with someone. They continued to own our house jointly and did so throughout their separation. However my mother always stated to my sister and I that if anything were to happen to her that she would like her half of her estate to go to us. Sadly a few years after my father left, my mum found life very difficult and she started to develop a drinking problem. This eventually resulted in her losing her job as a nurse and becoming a reclusive, only leaving her house to buy alcohol. My sister and lived away but returned every few months to clean her house and try and put her straight as well as talking regularly on the phone. Sadly, 2 years a go she had an accident in the house and passed away. As you can imagine this has been a very upsetting situation and I miss her dearly. I have since got married and recently found out I am pregnant which has bought me lots of happiness. However I am now having a lot of stress trying to sort out the ownership of my mums estate and would really like to get some outside perspective. Basically due to my mum's illness she did not have the capacity to write a will, although made her intentions clear to family and friends. My father also served her with divorce papers but she never got round to completing them. However unfortunately my dad has just been made redundant and at the same time sold the family home. My sister and I thought that due to the circumstances that he would automatically pass on my mums inheritance to us and honour her wishes. Unfortunately due to his own financial situation he does not want to do this and instead wants to invest the majority of the money so that he can live off the interest and pass the money back when we are due our inheritance from him. This has made me upset, angry and I have lost respect for Him as I feel like he is left my mother and now has no right to her assets, legally yes but morally no. I also live in a tiny house and with the arrival of a new baby would like to use the money to buy a family home which I know my mum would have loved to have helped with if she was still here. Basically I don't feel like talking to him , but don't want to deprive my child of grandparents but at the same time do not feel he cares enough about me to behave like this. I am basically trying to gauge if I am too sensitive about the situation and actually what he is doing is ok or if my feelings are justified. As I say I don't want to talk to other family and friends as I don't want to put my father in a bad light. Sorry for the long post and I would really appreciate your opinions. Sent from my iPad