The Dragon Sweater hit a snag

Apparently, Ann Budd did not take into account the wrist size of my 7 yr old when she wrote her pattern. I measure the child and his measurements are perfect for the sweater. I check my gauge. Gauge is perfect. I do my knitterly math and get all the right answers and yet, the sleeve will not go around his wrist. Okay, it is true that my wrist is 5.5 inches and his wrist is 5.5 inches. Perhaps that's the problem. He's fairly skinny, yet solid.
I informed my husband that I was NOT going to reuse that yarn again. I was ordering MORE yarn. You should have seen the look I got in return. I pointed out that said yarn is a mere 1.79 a ball. (There is the bit about spending 30$ to get the free shipping -- I didn't mention that)

So, I must leave my blog now and go cast on again. I'm trying to decide if I should do a bigger size or just increase the sleeve cast on by 4-5 sts and take out two of the increases. What would you do? Stuffing the sweater in the bin is not an option, the little guy has cried twice because he doesn't think the sweater will be finished by December.