How can I help my step dad?

My stepdad has schizophrenia. This has happened twice before, I can see it coming, he's on the verge of a break. My question is, how do I help him. How can I stop him from going over the edge again?

This all started when his son started asking for too much, even though he was told my stepdad couldn't afford it. He then got mad and started saying very, VERY hurtful things to his dad. My stepdad has made the decision to step back from his son, and we can see it's hurting him. We tried to do fun things as a family to get his mind off of it, and he was doing well for a while. Really well. He seemed happy. But now he's repeating the patterns he's done before, each time it ended with a stay in the hospital. Things were finally going well and I refuse to let him go away again, he deserves so much better. My mom watches him to make sure he's taking his medication, but he's gone out with his friend tonight and it's already 11:30, we're afraid he might not come home. All it will take is missing one dose, and he could be gone.

What can I do to help prevent another hospital visit? My mom can't take it, she's told me she feels helpless. I'm determined to help, but I just don't know how. He's not gone yet, there must be a way to calm this down, to stop things before they get too bad.