How can we force our father into Nursing home?

Check with local social services or state/county mental health departments. If he is in depression or dementia they can get him help. If you and your family continue enabling his actions and he is not well, it will just get worse for all of you. It is difficult and I am sure he will put up a fight when they ask him questions, but it can give you answers and they can help you find the right kind of help for both him and the rest of the family.I wish you all well