I think it's really sad that your mom won't let her "step-son" visit his father. It sounds like she has no relationship with him and simply doesn't want him in her home - thus limiting his access to his dad unless he will take him out of the house. I get why it would be easier for brother to just visit with his dad in his home. However, he may have no choice but to pick him up and take him out if he wants to see him since step-mom is denying access otherwise. I'd be tempted to ask mom if I could come over and then simply bring brother with me.