Advice on Fixing Fit of a Sweater

Hi Kids! I am having a knitting issue that I am hoping isn’t hopeless. About 2 years ago when I’d only been knitting for about 2 years, my brother asked me to make him Skully from the first SNB book. The pattern is for a woman, so when I first put it together, I could tell it wasn’t going to fit his armpits. I let it sit around for like a year, and then I came here and people helped me figure out gussets so I was able to finish the sweater.

He lives in southern CA, so was only finally able to actually WEAR the sweater this past Christmas while visiting our parents in the Pacific NW. It fits great except that since the pattern did not call for the back to be 2" longer than the front and I was too green at the time to know to make that modification, it hangs off his back odd - both too short, and kind of “away” from his lower back.

The problem is that the sleeves are a somewhat complicated intarsia, and they were cast onto the body, so I can’t do the obvious and just disassemble, add 2" to the back and reassemble. It would mean doing about 40% of the sweater over.

I was thinking of ways to cast on to the bottom to add length, which would be fairly unnoticeable because there’s no ribbing … but I’ve only ever done that in cases where I was adding length to the front AND back. I’m not sure it would look ok, or even achieve what I’m going for to just add 2" to the back.

I did consider that if I did the above, I could add a slight side vent, much the way polo shirts are sometimes longer in the back behind the vent than they are in front. But I dunno, I really thought I should check with the collective genius of this bb first.

Here’s the FO (modeled by DH)

Nice sweater, I like it.

I don’t see why you couldn’t do as you suggest and simply do the vent and add a little the the back, but is it really that noticeable?