The Custom is a good all around board. You might consider downsizing to a 154 but that's not a big deal. My recommendation is that you hit a local shop in Harrisburg and start with selecting boots. Getting a good fit is critical. He's probably still growing. Getting something that fits today and will work today and still have a little room for growth won't be easy. A shop can really help you there.
The reality is that there are dozens of boots/boards/bindings that can get the job done for your son. Choosing what kind of board (e.g. a freeride board like the custom) is a good first step towards narrowing your choices. Once you've set a budget, chosen to buy new or used, chosen where to buy (local store/swap/online), you choices to start to narrow. It's a tough job, but if you give up the surprise aspect and get your son involved in the process of choosing, he can help you end up with the best choices for him.