Can he? I'm sure he can. Can he do it at a first grade standard? Most likely not.
Sheens basically ruined Tim Moltzen's career 10 or so years ago trying to turn him from a half with potential to a failure at fullback when he was only in his early 20s.
Brooks is going to be 28 soon, maybe he can transition to a full time 14 but that's about it. No need to experiment to fit him in the team anyway - he's not a "must play" calibre player. If he's our best 6, he plays there. If he's our best 14, he plays there. If he's not either of those, we drop him/let him go elsewhere.