Our DS has a developmental disability that affects his ability to cope; he has thrown tantrums in the past. So my response comes from the perspective of W and his parents, assuming W has a disability, which I find very likely from this description.
1. The teacher should, with W's parents' and W's consent, address W's differences head-on with the class; first without W present, and then preferably with W present as well. Everybody needs to understand that W is different because of [whatever], that W is trying to control his temper, but needs support and understanding from them.
If everybody's pretending there's no problem, it's very confusing for all the children. Better to acknowledge, explain, and educate.
2. The school needs to get enough support into that classroom that there is someone present to help W handle himself. That means an extra adult who can remove him to a calm-down place when he needs that. It isn't fair to W or to the other children to have one teacher managing teaching plus the extra need.
As a parent, you can go to the teacher and supportively suggest that you've noticed there's a problem and that your DS is scared and confused and distracted. Without going ballistic ("why are kids like that in this regular classroom") or extreme ("I don't want him anywhere near my kid") you can suggest that the teacher ask for extra resources. If s/he is reluctant to, you can go to the principal to advocate for those resources.
Thanks for encouraging your DS to have understanding for others' struggles. I have found that having the teacher (and special ed teacher if appropriate) explain what the problem/challenge is, to the whole class, makes other kids less fearful and more accepting. I can't tell you how important this acceptance is; and, paradoxically, how much easier acceptance makes it for a kid who struggles to get it together and behave.
DeeDee
