Sadly, since he's four and a half, "normal" is probably too much to expect.

But, if we can stop the seizures, he might be able to start learning.

He advanced very rapidly during the two month break from seizures that he got from ACTH.

If we stop them soon, there's a good chance he might be able to walk and talk some day.

Regardless of how far he develops, he'll be much happier than he is now.