Erectile Dysfunction

My fiancé is 55, I am 27. I have eight year old twins from a previous relationship. I love him so much and the age difference doesn't bother me. When we first started dating we didn't have sex until four months of getting to know each other. I loved that about him,until we finally did it. Oral was amazing but he could not please me doing intercourse and he blamed it on the alcohol. So time goes by and he continues to blame it in the alcohol because he's having three 40 oz a day. We've been engaged for seven months and he has only "came" four times. I noticed that when he's "jacking off" he will cum every time but his penis is soft even when he does cum. He has no children of his own and is excited to be a father but I'm afraid it will not happen because he will not go see a doctor to address the issues. I do not think about cheating but sometimes I feel like I'm putting my hopes and dreams of a family with my husband on hold . What man doesn't want to cum inside his woman to have a baby. It's gotten so bad he wants to try the syringe method to get me pregnant and I've said no. I want him to see a doctor. Has anyone ever dealt with a man like this? Should I wait it out a little longer or is he truly too old for me?