Well he needs a larger board for sure. I would go anything from a 130-137. Considering that he's probably growing like a weed, something closer to a 137 would be ideal, that way it'll fit him longer. As for his feet getting bigger, the waist width (how wide the board is) around this year's Burton Chopper 125cm (they don't make a 126) is 230mm. So I'm guessing that's really close to the waist width of the board your son has now. So you need to find something with a considerably larger width than that. Especially since he'll probably be in size 8 boots before you know it. The Burton Dom Grom is one possibility. They make a 134 and it has a waist width of 237mm. It is however geared more towards a park board. The 135 Custom Smalls and 135 Custom V-Rocker Smalls both have a waist width of 234mm. These boards are also both geared more towards park, but could be used all-mountain as well. I'm not sure how much his boots are hanging over, but if you don't think 4mm or 7mm is enough extra width, then I would look into something that is obviously a little wider. You can search the site for other kids boards that backcountry has. They unfortunately only show the waist width for one size of any given particular snowboard, so you have to go to the manufacturer's website (like burton.com) and research that particular board there to find out how wide they are (waist). You may want to look into getting him a woman's board as well. Many of the woman boards they make today look just as cool and similar to mens boards, and they would offer a little more flex, have a wider waist than junior boards, and be more suitable for someone his size. Hope this helps! Goodluck!