I suppose since the IRS is not in the business of reading divorce cases, if he doesn't claim the alimony deduction, they aren't going to try and match the income somewhere. They don't ask how much money I spent on video games for my kids cause I don't claim a deduction for that, KWIM? Definitely run it by your lawyer, I'd be surprised if a judge would allow it, but I don't know. There's the "law" part (judge) and then the "tax" part (IRS). Just because a civil judge says something, doesn't mean the IRS will agree.
The actual regulation is here: Section 71(b) of the Tax Code.
In my effort to be *concise*, I often come off as blunt and harsh. Sorry, don't mean to be offensive.