Child Custody and Alcoholism?

I’m due to give birth next week and I am no longer with the father because of his heavy drinking. I want him to be in my sons life as a positive role model but I am scared for him to have private visitations. How am I supposed to provide proof to the courts of his alcoholism? And will they order him to get treatment before he has unsupervised visitations? He does have 2 DUI’s, drug charges and a stay in rehab, but they are over 10 years old.

I live in Massachusetts