Even a tune up fight would be fine. Say what you will but Wilder has exciting fights even with lower level guys.
Horrible matchup for Helenius, Wilders straight right would take out Robert . If Dubois beat Lardo Bryan, Dubois would be a good come back fight for Wilder. Wilder would take him out in one or two rounds. If I were Dubois management I wouldn't take a Wilder fight, I would hold out for a D. Whyte fight in England, as Whyte's chin has been cracked one time to many.
Helenius and it would be an easy fight to make. Good payday for Robert and opportunity for Wilder to get another title shot.