He'd need to find another EL side if he dropped down anyway. Can only have 2 FT DU riders in your side. A third one can only share with one of the others, PLUS you have to be in a declared 1-7 in the PL.
So he'd need to leave BV, sign for a PL side and then sign for an EL side who dont already have two double uppers, unless he wants to share an EL spot!!