Good tips.

Not just gambling. Any kinds of addiction are usually bad for one's family. Addiction on substances, alcohol, women (yeah, even women) can cost one's family or even worse, one's life. Everything should be on moderation.

If you know of anyone who's in such category, help that poor fella. Send him for a rehab or send him to a shrink before it's too late.

I wish your sister all the best. She seems to be a rational and thinking kind of person to me and I hope she has made the right decision.