If your son is smart, you have to force him to go to college, learn to drive, delay gratification and take an interest in science. He's not losing his virginity in school, but if you manage to trick him into getting a higher education, he can get a good job and eventually girls will be attracted to his money. He might not have kids, he might marry a Southeast Asian, but he won't die a virgin.
If he's average IQ or lower, treat him like shit. Don't do anything for him. Beat him if he talks back to you. If he gets a pet, force him to drown it with his own hands. This will turn him into an evil cunt - and women love that. There's no fucking way he'll be an incel. He'll fuck half a dozen girls before dropping out, maybe even one of his teachers. Since he's borderline retarded, at least one will get pregnant, too, so your blood will pass on, which is better than having a nerd for a son. He might kill you, though.