Trouble at school...

Does anyone have any advice on how to modify poor behavior at school at home? My boyfriends son (who is almost 7 and in the first grade) gets into trouble at school on a daily schedule! Even on minimum days. My boyfriend has spoken to the teacher, observed his son at school (which was a waste) and has to the lazy BM that she needs to be concerned about the kids behavior (she is the "fun" parent who treats him like a friend). Anyhow the teacher has basically told them that he is extremely disruptive and does as he pleases regardless of what is going on in the classroom or on the playground. The teacher has told them she is trying a variety of things to get him to make better choices. The kid has been checked for ADHD but appears to just act like a brat because he thinks he can. Now I had mentioned his poor behavior to my boyfriend after the very first time I met the kid and was concerned. At first my boyfriend thought I was overreacting but now that the school has gotten involved he's listening to what I'm saying!

So here's the main problem I feel (as does my boyfriend) there is only so much the school can do to punish him so it's up to his parents to modify and encourage acceptable behavior at school by how they handle bad reports from the school. Problem is my boyfriend is strict and tries new ways to punish and reward kid but his BM doesn't do the same thing. She literally has told my boyfriend "when he's with me I'll punish him my way, when he's with you you punish your way!" So awful and inconsistent for the kid! Do any of you have any suggestions of what my boyfriend can do on his own to help his son behave better at school that doesn't require BM involvement? I know the answer is probably "no" which sucks since the kid goes week on week off and really needs both parents home enviornments to be somewhat similar! But I thought I'd ask! Thanks-