Try soaking his thumb in water to create some more space between his skin and the splinter… or if it isnt practical for him to soak it for that long of a period maybe put a bandaid over the entire area first and then keep the bandaid wet for aday or twobefore attempting to remove it again. The idea is to create the effect where the skin gets all puffy & wrinkled like when you stay in the swimming pool or bath tub for too long.