Taking action from just one person?

Is it profitable to take action from just one person? I know someone who took NFL action from just one guy. The guy was betting $100-$300 three team parlays every week. He was down a few k, then came back and won about 8k. This guy went on an insane heater. Would it make sense for that person to keep taking their action? This guy apparently also bets boxing, mostly favorites. I would think someone who bets heavy parlays like that will eventually lose their shirt. I understand having more bettors absorbs the losses for winners, but even still, one person betting is a positive expected value situation for the person taking it, right?

If he continues to bet long-term everyday, YES. You will turn a profit.

If he is the kind of person who will quit betting once they win a few K, or if the guy taking action has a limited bankroll, I wouldn't do it.

My point exactly Thorpe!  

The guy definitely wouldn't stop betting after winning a few k. The guy bets every single week of NFL, mostly parlays and almost always favorites. 

Is this one of those, "I, er, know a guy...." scenarios? Are you the guy?

No, it just got me thinking. My thought was taking action from even just one person would be +ev. But being down so much could be pretty discouraging for the person I know taking it. I suggested he limit him, but to continue taking it. 

Ideally, as long as you are both in it for the long run, and are on a set payment schedule, he will likely lose BIG over time.