There is no such thing as a domesticated tarantula, just as there is no domesticated snake - only ones we take into captivity or ones we breed in captivity. They are still wild, some just put up with human contact better than others.
There are a couple genus of tarantulas that are usually readily handleable - Grammostola, Brachypelma, Avicularia, and Aphonopelma. Just take him to a place around you that sells tarantulas and have him watch people handle them or have him handle one himself if he is up to it, some times if people just have one walk over their hands they kind of respect them more. Other than that you can't really force anyone into liking tarantulas or any spiders, but I have found that many people like tarantulas more than smaller spiders because they are "furry", I have even had people tell me they remind them of hamsters lol.