No doubt your 2 eldest children are having a hard time adjusting to the twins AND their "disruption" in their family, because of it. As you know, children act-out, when they are having problems. As is the case for your children.
If anything, and if you cannot handle this on your own, it might be a real service to them, if you can get them counseling. Sometimes we Parents cannot do 'everything' to help our children and we need outside help.
For your kids, the problem is obviously adjusting to the new babies. Children experience "stress" as well... and they are obviously stressed out by all this. It is really imperative, that they get help with this. And right away. No dawdling about it. Your kids are in great need right now.
Kids also need LOTS of one on one time with their Parent(s). AND being able to talk story, to vent, to express their feelings... in a safe and "non-judgmental" way, so that they feel open about it. You do NOT want your kids feeling "pent-up"....and "helpless" and apathetic about all this.
Perhaps, explain your situation to the Teachers...openly. Then it will paint a bigger picture for them in understanding your children... and how they need help.
It can sometimes take time, for a child to stabilize and to feel "happy" about everything that changed for them in their life... they need "balance" again, and to feel it in their home.
To look on the other side of the fence: In my daughter's 1st grade class....there is a boy who CONSTANTLY makes trouble to the others... and disrupts the whole class. The Teacher is constantly having to monitor him and correct him. For the kids on the other end of the stick, this boy REALLY upsets them, makes them unhappy, makes them stressed out and irritated. For the Parents who hear this from their child...it is NOT a positive thing to hear...and it is equally upsetting. For me, when my daughter comes home and complains about this boy...almost everyday... it is VERY upsetting. VERY. I have even talked to his Mom about it... and all she does is make excuses for him. For example: One time my girl told her son to "Stop" making trouble AND before I could even utter anything out of my mouth, this Mom talked over me and made excuses for her son to MY daughter saying-"No, he's just a very active and imaginative boy, and he's very physical... so he's just having fun, you have to understand that...he's just funny that's all..." And my daughter's eyes looked up at mine and she looked so sad and her eyes turned red... So I stepped in and said "BUT, it's not funny for the other kids... there is a time and a place for that...." And I told my daughter in FRONT of that Mom "It's GOOD sweetie that you spoke up... you are right. It's Important to speak up and say what is on your mind if something is bothering you or tell the Teacher...Good girl..." BUT, that is not good enough... I don't care about excuses from that Mom... I just want the boy to STOP making trouble to my daughter. Why should my child have to "suffer" because of this boy and have HER learning experience suffer???? My daughter gets very stressed about it and this boy is just a ball of trouble. It is very disturbing.
THUS, I say... there are many sides to this- your child's home life, the trouble it brings to other students in class, the burden is brings to the ENTIRE class & to the Teacher... AND, then, what is going to be done about it? There are MANY MANY people being affected by this. SO... something has to be done.
AND, what if the other Parent's start to complain about it??? What then? What about your Son and how it will affect him? How will it be handled???? You must think about this, and nip it in the bud... both at home, and for the sake of his being a "student" in school.... these are "responsibilities" of any situation like this. Obviously, your Son is already stressing out the other kids... they "fear" he will make them lose "good behavior points"....and honestly, I can understand their worry about this. I"m sure you can too. So you see, it's affecting EVERYONE.
Yes, I TOTALLY empathize with the hardship this puts on your eldest children... and their school. BUT, you have to tend to their needs as much as you can, to make sure the are happy again. Thus, I say, perhaps counseling for them might be a good thing.
If what you are trying is not helping your children (ie: you and your husband giving them as much love and support as your can), then you MUST try other things. And, there are lots of suggestions here.
You also mention that you work part-time from home... so plus with your twins... is that impacting your 3 & 6 year old too? Do they get much face to face time with you? My daughter is expressive and just last night she was quite fussy, I asked her "why" and she point blank told me "Because you didn't spend time with me after dinner like you said you would..." And she was right... I had "forgotten" amidst all the other things I had to tend to before getting my 2 kids ready for bed. My daughter had been "waiting and waiting" (her words), and she finally got fed up with my not remembering. Shame on me, and I apologized to her and told her "I'm very sorry, your'e right. Mommy forgot, will you forgive me?" And then, we were back on track and she was happy again. I dropped whatever I was doing, and spent time with her. Kids need to SEE this and even to hear US "apologize" to them too.
I empathize with you and really feel for you. But just as a Parent who's daughter is affected by a student like this... I just wanted to elaborate on "how" it affects a whole bunch of people... and thus, your Son is getting affected by it all as well. No child, can handle this much stress and turmoil from ALL sides. You have to care for his emotional health and well being. He probably feels really marginalized, and "lonely" and "isolated" and alienated by all this... both at home AND at school. This is too much for a young child to bear.... he can't carry the whole world on his shoulders. Your 6 & 3 year old need more help. It's not just a "school" problem, it's their home-life that has to change so they are happier. School problems are just a symptom and result of it.
All the best,
Susan