They changed the law back in the ‘80s so Congressmen/Senators/candidates no longer get to keep their campaign contributions as personal funds.
They DO, as I recall, get to decide where those funds go, however. He can give to the DNC/DCCC/OFA or maybe given how supportive his Dem colleagues have been, to the Salvation Army.
He could start a non-profit and pay himself a salary. I think Newt can show him how to do it.