It depends on the facts:First, he (or she) would only be liable if at fault: that is, if the Santa deliberately dropped your child, or if the Santa were negligent, or unreasonably careless, in how he/she held your child. But if dropping your child were not the Santa's fault--someone else bumped into the Santa; your child struggled and wriggled so much that even though the Santa tried to hold on, he/she couldn't; etc.--there would be no liability.Second, even if there was liabilty, if--hopefully--your child was not injured, there is nothing to sue for. The law only provides compensation for actual injuries or costs; without injuries (or significant medical costs), there is no point in suing, since you could not recover anything.