It depends on the tattoo and where it is. If its on the face or neck, not my thing personally. He regrets having one when he was young (and in the 90's) and is very out of fashion now; so be very careful when choosing a tattoo and its design and where it is. Fortunately he can wear a long sleeved t-shirt so can cover it up.
Daughter wants a tattoo of the lorentz time dilation equation (shes a physics degree student) so its means a lot to her.