Seventeenth Zither
If he had those friends why not pool all their resources into building a bigger bunker with more supplies? At least he wouldnt go insane from isolation and would have a better chance to repopulate the planet if he was the only one to survive.
Shouldn’t have rejected the girls... now what’s gonna happen if you’re the last man on Earth? Mate with a pig? Congratulations, you survived but your entire human species didn’t. (ノಠ益ಠ)ノ彡┻━┻, on a more serious note his “semi-professional” bunker probably can’t compare to the best bunkers sponsored by the main governments, so this is a non-issue.