This is morally, ethically and plain wrong. He needs the endorsement and good name of well-connected bitcoin professionals to be linked or attached to his ICO. There is always a motive for such things and the only one I can think of right now is a fishy one.
Let's change gears.
What happens if PETA gets a celeb to endorse a campaign for their protest against seal hunts?
You're basically hiring an endorsement.
Similarly, there are instances where celebrity tech enthusiasts, super models etc (like Karlie Kloss) gets approached by saas companies (like Wix) to endorse their product.
Please, tell me how it's different. For one, it'll prevent the likes of me from joining the fishy people, and secondly, there'll be a clear consensus about what's right vs what's not.