ITS better for him not getting any fruit.. his job is to fish any troublesome member out of water (devil fruit user)..rather than that better upgrade Robin and Chopper fruit
if you must at all cost give him a fruit give him one that is only utility please so power up by fruit on the swordman please maybe making his sword eat the fruit?
Truth fruit just lets him force people to tell the truth or map fruit just gives him a map and you decide if he gains or countines with his sense of derection