So you are advocating mortgage fraud. Interesting.
Not to mention that he would then be responsible for the taxes on the larger salary.
I'm not advocating anything, I assumed he has the means of paying the mortgage but not the ability to prove it to the bank, (and as I side note, my mortgage broker gave me this idea, obv. Unofficially) and yes, it might be worth paying taxes on higher salary for the few months until closing.