I would give them 30% tops and that's like the final negotiation step "take it or leave it" kind of thing. Also for the love of God give him a 1 year cliff, 4

I would give them 30% tops and that's like the final negotiation step "take it or leave it" kind of thing. Also for the love of God give him a 1 year cliff, 4 year vesting schedule. DO NOT just cut him equity. Other comments here also properly note, you may not even need a cofounder. Just hire a commission based sales dude. That sounds much better.