Anne Audain of New Zealand, at one time in the 80s labeled as "the winningest road racer" in the US, had deformed feet in her childhood. She had a surgery and docters thought she may not run again. But they also suggested her to wear, as one other person suggested, wear minimalist shoes to "strengthen her feet". She trained in the racing flats throughout her athletic career.
At the age of 11, his feet are still developing. In my opinion; without knowing exactly what the problem is or what the doctors diagnosed or what they have in mind; wearing heavy motion control shoes or braces are the wrong direction.
When I was in high school, my dog had several puppies. One of them had a deformed foot (left front paw). It didn't hold itself and collapsed inward and backward when he put his weight on it. The vet put a cast for a while and it didn't really help (it came off); then he put a brace around it and that didn't help either. Then I noticed when he tried to run on it, once in a while, he would hold himself up. So I went the extreme and let him run around. He fell a lot for a while, but then after a month or so, it completely healed itself. This was almost 5 years before I became acquainted with Arthur Lydiard but his voice ringers in my ears; "If you have a weak spot, you need to strengthen it; not to support it."