Relationship advice please?

I am to my wits end and need advice quickly to try to save my marriage. I am to the point I don't see any chances coming available to save it. My husband works delivering pop he goes in at 4 or 5 am and doesn't get home until sometimes 7:30 or 8 pm. When he is here he doesn't even act like he wants to be here he just kinda sets off to his self. I have tried to talk to him about it, but when I do he either just acts like he listens or acts like he is falling asleep. I can ask him a question while we're talking about things and he just answers yea like ok go ahead and shut up. I tried just ignoring the fact for his kids sake because their real mother was found guilty of neglect on them, but now his 4 year old little girl seems to understand more than I thought. Today is her birthday she has yet to hear the first Happy Birthday from her father. I was going to go to my mother's house this weekend to help her out hoping it would give some time for her to spend with her daddy, but she doesn't want me to go because she says "Her daddy doesn't seem to know she is here." Today was also their health department appointment that he was suppose to take them to due to I can't drive right now over having one seizure. He claims his boss won't let him. The appointment they had today has already been rescheduled 7 times due to I have no one to take them. I can't do this anymore. All I want is things to be civilized to where he understands that he has a family that he started and to actually care, but I don't know how else to make him realize that. I have already came to the point if this weekend is the same as everyday attitude for him I am going to file for a divorce Monday morning. I don't want to because I know I am all these kids have, but I can take only so much. Someone please help!