I used to hand off to him all the time, just because you can't bench 500 doesn't mean you can't spot 500. My GF has spotted me a many times on +500 benches and + 600 squats , shes not weak by any means, but she not as strong as I am. Also i have been lucky enough to train with groups or teams of lifters, some stronger, some weaker, all competent to spot and load.
My point about training with people stronger was the motivation and inspiration they provide. If I was worried about safety I would train on the smith machine with the rest of the pussies.