How would you select the winners? Will you use blockchain or randomly generated numbers to pick the winners? Are you going to escrow the funds? What could increase our chance of receiving the first prize?
Judging by his negative trust, I'll tell you what will likely happen.
1) He'll rig the "giveaway" so his alts/friends "randomly" win it.
2) There will be no payouts at all
The only way to trust OP is if he hands over the giveaway selection to a trusted 3rd party and escrows the funds beforehand. Until he does this, do not do anything he asks.