I was trying to do that mini quest, where you have to scrounge up the illicit arms for that NCR trader in Camp McNarran. I forget his name right now. But Isaac was nowhere to be found by the Gunrunners booth. I kept going back there for a few days but he was always a no-show. I knew he went home from time to time so I decided to head over to his place and see if I could talk to him there. I found him lying fast asleep on the bed, but I wasn't able to wake him up. It's been quite a few days now since he's been around the store, so I can't initiate that mini-quest. Not a big deal as it's just kind of a side thing, but I find it kind of annoying. I can't figure out why he can't make it through his sleep package.

He's been killed by a random Fiend in my current playthrough, you might find his body somewhere near.

I did find him. He's fast asleep in his home, but he won't wake up. I tried talking to him to get him out of bed but he won't respond. And I know he's not dead since I can't access the stuff from his corpse. He's been sleeping now for ages. It's one of the strangest things I've seen in these games, I've never come across this kind of situation before.