Help me please!

My husband has a four year old son with another woman (I'm okay with that.) Last week was our first time in seeing him in over a year, she kept denying us the right to see him and then put it on her ex saying he was denying and deleting messages. My husband works a full time job. We planned to meet on Thursday morning so he can see his son (he only gets one hour a week once a week court ordered) well she changed her mind saying he can't see his son on Thursday because it is supposed to rain. She doesn't drive nor have a job. She told me we have to change our schedule to see his son because she won't change hers. My husband loves his son to death but he is starting to not feel like the father because of her basically denying him the right to see his son. Some of her friends and family message my husband on Facebook calling him a deadbeat and he has been depressed because of it. I don't know what to do because I want to help and I did by setting up the time to see him last week but she's pulling this and he is getting upset. I just want what is best for my step son and my husband. What should I do? His son also made the comment to him while they were on the merrygoround "I'm drunk. I'm drunk. I'm drunk like papa"