I didn't find the pattern 'girly' but the yarn you select will help determine that. If for boy, use a yarn that you feel suits him.
Besides what Jan sugg, if you still feel you need to increase one sz beyond the largest, you could inc st count to include one more patt repeat in the body. However, if you opt to add a rep, you'd need to recalc the working numbers for shoulder/neck to reflect the change ...but which wouldn't be all that difficult. The sweater is fairly unstructured and loose in the body so fit isn't super crucial.