You need to talk to a therapist and a lawyer. For custody, it isn't okay for one parent to turn the children against another parent. Him calling you "mommy meany" is a huge problem. Your lawyer can help you document that and fight for custody. Also, their therapist can help, especially if you get therapy with your children. Along with that, if he has custody and doesn't feed them, you document that and tell your lawyer. Him refusing to care for his kids while they are in his custody is neglect.
You have now posted three times in a week asking for help. But no one can make your husband care about your children. No one can fix your children's eating habits because your husband doesn't care and may actively be against them if they are autistic. We cannot force your husband to love or care or accept your children. We cannot force your husband to feed them healthy meals rather than junk food. We cannot force your husband to be patient with your children's food aversions and take the time to find healthy meals they will eat
But you can protect your children. You can be a strong, encouraging, loving mother. Start taking steps to leave your husband, get your children diagnosed if they have autism or ADHD, and look into counseling for yourself. You've stayed with a man who actively made fun of your autistic brother and it would be helpful to discover why. It would benefit you and your children to be mentally strong and you leave your husband.