Please help, my kids school is screwing him up

Throwaway because I don't want people recognizing this story somehow.My kid (7 yo) is in 2nd grade and he has a horrible class. It's starting to influence his behaviour as well and I feel like all our parenting efforts is one step forward two steps back, with the two steps back being caused by school.My kid has always been a very gentle kid. Always very empathic, even as a little toddler, never violent, just very sweet natured. A bit shy. Don't get me wrong, he's far from perfect and has many issues that need work, but being violent and disrespecting adults has never been one of them.He has a new class, and there are 4-5 kids that have huge behavioural issues. Like throwing chairs through the classroom, biting the teachers, using foul language, hurting each other to the point where doctors need to be visited, big issues. Because of this the days in school are mostly spend getting these kids under control, there's hardly any time left for learning. School results of all kids are suffering.We've already had many talks at school about this, as did some of the other parents, and things are changing. More help for those kids, more help within the classroom, and many other things were agreed upon and I'm hopeful things will change long term.However, at home my kid is starting to copy the behaviour of those kids. Like yesterday he kicked a three year old in the playground because he was irritated with him, today he told his little brother he'll 'stab him with a knife' because he didn't listen to him. Similar incidents occured over the last months. He seems so angry and volatile all the time. Maybe I have an overly positive image of my kid but it just doesn't seem like him.There are clear consequences for him (in the playground we made him apologize and then left, today he lost the right to use knifes) and we've had many talks with him on how we notice his behaviour changing and how sad that makes us, also because we know he can do much better. Sometimes that helps for a little while, but it keeps on being an uphill battle. Behaving this way seems to be his new 'normal'. How do I stop this? I feel so lost on what to do, everything I try seems to fail.. via /r/Parenting https://ift.tt/2qfyn9j