My other concern in this response is the way they've apparently apportioned blame equally (which frankly is a soft option result, saves them having to really work out what is going on) and that the promised support will evaporate like snow at midsummer next time this other kid hassles difficult child 2.
It is typical of how the local school 'resolved' problems for difficult child 3 - in one case, difficult child 3 was chastised (and I got notes home) saying that difficult child 3 had screamed at a pregnant teacher and had later thumped another boy when nobody was looking. By the time I got to the bottom of what had been going on we had a weekend to deal with and it would have seemed incredibly nitpicky and pointless to stir over the mess. But the problem began when teachers did not intervene when a boy (the one who was later thumped) kept sticking something sharp into difficult child 3. The kids were milling around in the school hall (unstructured time with minimal supervision in the school hall was the reward for performance in the school choir) and when difficult child 3 complained, the staff asked the other boy, "Are you sticking things into difficult child 3?" He of course denied it, difficult child 3 was told to stay away from the kid (as if that is possible, when the other kid is determined to seek him out) and at this point difficult child 3 screamed at the teacher for the idiocy of this response. Her pregnancy was not even an issue for difficult child 3 - he didn't know about that sort of thing.
And then later on when difficult child 3 had to go to the classroom to collect his bag, the idiot staff actually sent this other boy with him, so difficult child 3 wouldn't be left alone! I don't know what happened at that point, probably another pin stick, but difficult child 3 thumped the kid, and I found out several YEARS later, that the teacher then visited the other boy's family and advised them to press charges of assault on difficult child 3. To their credit, they refused. That kid kept hassling difficult child 3 over the years until I finally said, "Enough!" and went to talk to them. That is when the rest of this story came out.
So beware of the lazy response form the school, that does not resolve whatever is going on with this other kid, to have him hassling your child. We had to dig a bit deeper and I had to take affirmative action. I made a huge effort to explain to this other kid that attacking difficult child 3 was no glory (like shooting fish in a barrel). I discussed bullying with him and said, "I know you have been bullied too. It's not fair. But you don't deal with it by merely passing the pain down the line. That's not fair either, and it doesn't stop you being bullied. You need to find ways to make it stop, and not keep the cycle going."
All I did was make it clear that I knew what was going on, and it was going to stop. I would not tolerate either boy hurting the other. OK, again I made it seem equal, but that was also to make it clear that although this was MY child, I wanted him to learn to not hit. But in order to achieve that, I needed other people to not make my job too difficult. I also made it clear (because this kid was trying to say what had always worked before, "difficult child 3 started it" when I knew it was a lie, there were witnesses this time) that difficult child 3 does NOT lie, nor does he start problems.
There was one more incident (involving different kids) which should not have helped things, but I think it did. We were at the beach and the same things were happening - GFGe was getting hassled by kids who would not leave him alone. We moved to another part of the beach, and these kids followed him. Finally I said, "We are going home." It seemed the only way to stop this. husband was with me, and we called difficult child 3 to us. He began to walk towards us, one of these kids must have said or done something because difficult child 3 suddenly turned and attacked. He had flipped totally, and the kids backed up fast, but not fast enough. One went down in the shallows and difficult child 3 was on him, fists pumping like a piston. husband dragged difficult child 3 off the kid and I was ready for him to really get angry with difficult child 3. But no - husband went for the other kids. He must have heard what they said. husband did what I should have done years ago, and told off the bullies, said he was very willing to come to their house and discuss the matter with their parents if they thought he was being unfair, but told them that their provocation of difficult child 3 was the entire cause and that they deserved everything they had got. And said we did not want to ever see them anywhere near any of us again.
We never did.
These kids had mostly been visitors to the town, following the example of one kid who had learned, along with all the other kids at the local school, that difficult child 3 was a safe target because teachers would not step in, or would blame difficult child 3 for the problems. It took us getting involved (not generally recommended) before the local kids got the message that attacking difficult child 3 would bring down a heap of trouble onto them. Including the police, who we began to call for every little thing after that.
So go carefully, watch and be especially nervous about difficult child 2 getting the (wrong) message that asking for help is a waste of time, because it is his lot in life to regularly get into trouble.
Marg