Evaluate this drinking prop bet

[Seether]

So while drunk tonight my friend makes some joke about taking a bunch of shots and throws out the number 80. I say he can not take 20 shots a day for 4 consecutive days. He is a college student and drinks a bit but he doesn't have some ungodly tolerance. He weighs 200lbs.

I am laying him the odds of 8 to 1 on 100$. If he throws up within 30minutes of taking a shot the shot is added back to the total. If he does not throw up a single time he receives a 100$ bonus. I clearly have the best of it in this right? I figure he can make it through day 2 but day 3 and 4 should be hell for him.