The chances are far greater is he is not represented by an experienced criminal defense attorney. The only control a defendant exercises once charges are filed is who his legal representative is. If you want to help him, help him secure the best attorney possible to represent him.
I suspect your post is missing some key information. As Mr. Kaman pointed out if your brother was on a public beach, that doesn't sound like trespassing unless he was specifically prohibited by his probation conditions from going to that beach, which doesn't make any sense. When you say he is facing 5-7 years in prison for a violation, it sounds like he may have a suspended sentence hanging over him. Based on what you have written and recognizing that we don't have all the facts, including whether he has a suspended sentence hanging over him, he's probably not go to state prison.