Based on your post, I would, yes. I tend to go with "work" being subject to self-employment tax, even if it's a one-time event. I believe "other income" is, well, income from something other than work, like a prize or debt cancellation. Lots of tax pros better than me would never subject income to SE tax for a one-time activity, like that week of hanging vinyl siding for the general contractor, but this is not that. Shoot, the real experts think practically nothing is subject to SE tax, Schedule SE should be seen less frequently than a Unicom, and I should just hang it up.
I would of course ask him to provide legitimate expenses. I assume he has some if he's not looking to make a profit. Or do you mean he would do this work even if not compensated? I guess my answer is the same, either way.