A.C.
Yes, I have heard that these supplements are a good way to get omega-3s into kids, if for no other reason than they will actually take them. And he seems to think that they help him; sometimes, the placebo effect is oftentimes the best solution. I'd say if he likes them and takes them and says they help him, I'd continue giving them to him.
My daughter takes a 750 mg EPA-DHA fish oil supplement. I have noticed a tremendous difference in her ability to focus and stay focused. So yes, I do believe omega-3s are good for you, whether you get them through eating fish/shellfish or taking a multi.