Is this too much candy for the basket?

Personally I think it is fine. It is not like he is going to eat it all at once. My kids get a bunch of candy for Easter and I always put it in a big bowl out of their reach and it lasts for months. If you still think it is to much sugar you could also add a few pieces of fruit, raisins, etc. Also instead of putting it all in the basket why not have a small egg hunt for him. He would probably have a lot of fun trying to find everything. Also I think it is really nice that you are thinking of him.