It was only once, he was a acquaintance. I did not much about his personal life of his habits when came to gambling. Though, it turned out there was a new casino in the city and he started to get much fun there, until he got addicted without even realizing it.
He lost much of his cash and his possessions and the last time I knew about him, He was selling his truck to settle down his gambling debts.

How are we supposed to react about them? He must have empathy, I think. We are talking about people like us, after all, and addictions like those are something which could turn our life outside down at any time we we are not careful enough. So that is what one is supposed to feel: empathy and understand that there is nothing to be done if the person is not willing to change their life.