A lot of young men are sucked into this world, what you have described is exactly what I took OP to be looking for.

They might get them a membership to a gym or tools for a hobby that allows them to socialise outside of online.

Op mever called their son a fascist or mentioned they want them to believe the same thing. Fascism is harmful, thats why even the fascists call the others fascists, it is not a bad idea to want to realign someone’s viewpoint with reality.