So I got myself a Mr. Handy and sure enough he died during a ridiculously overpower RadRoach that took well over 100 shots to kill. I left him in a fully upgraded Living Quarters until I could revive him. This morning I woke up and decided to expand my Living Quarters and built a 2nd room by it and upgraded it so they could merge. Apparently this also revived my Mr. Handy, but with a catch. Mr. Handy is still classified as broken/dead so I can't tell him where to go, but he continues to fulfill his normal work like usual even against Raiders. He has no health bar and I haven't seen him talk or suggest anything that he's going to die and I checked, he is actually hurting enemies and putting out fires so I can only assume he's immortal as my other Mr. Handys break after 3 or 4 raids and he's been fighting off raiders and RadRoaches like a god, surpassing 8 raid attacks. Just thought I'd put it out there. I'm not sure if it'll work again since I haven't tried it, but it's worth checking out if you want to try getting an Immortal Mr. Handy.