What kind of help can I get for my Uncle who was diagnosed with dementia but has always been an alcoholic and still is?

He seems to be fine when he's not drinking but he is very hard headed and will not listen to anyone or consider anyone's advice. He has recently been drinking a lot more and when he does it is excessively. Which is causing him to get more confused with things involving the police. This weekend he almost struck my cousin who had her 6 year old daughter standing right next to her. What can we do for him? Another thing is that he is my Uncle by marriage my Aunt who he married passed away about 10 years ago. His own family wants nothing to do with him because of his attitude. Although his own niece moved him from California down to San Antonio once he told her things she didn't like she was gone from the picture.