Mega and other drive services would be best @DonkeyCart. Adult content is absolutely allowed on Mega. The caveat is they respond to copyright complaints like everyone else, but that's not unique to Mega.

XVideos is owned by the same company as PornHub. Tubes in general aren't reliable.

It'll all depend on how much space his collection takes up and if he's willing to pay for storage @thevip . He has over 1000+ videos, so the free 50gb that Mega provides may not be enough as opposed to a porn site which technically has unlimited storage for free uploads.