Can anyone help me please????

I have an autistic 4 year old who is the size of a 5 year old. He is about 46lbs and 3 feet 8 inches ish. Anyway, I need a stroller that will carry his weight. He CAN walk, but... he will pull away when he gets overwhelmed and try to run and hide. I plan on baby wearing when we have baby number 2, but I will really need a stroller for him. Any suggestions?