I got really worried over the habit of some friends who are into betting or gambling and how they often stake into a game in a week more than what they earn even in a month and most time are not able to get it back in a couple of plays. So it got me really worried and concerned
What would be your advice for such if they were to be your friends as a caring friend who want them to not get financially drained in the process?
You don't really have a lot of options here. Even though they are your friends, you can't really force them to do anything unless they are always ready to listen to you, and you are confident that if you tell them something, they will understand and stop doing it instead of getting mad and arguing with you over it.
Most people who are into gambling and have got a habit of doing it and do it excessively, they mostly have a short temper, and they tend to get angry or irritated very quickly, so if you try to school them over it, they might take it seriously and start arguing or fighting with you over it.
That being said, there is nothing wrong with trying. You should find a perfect situation, and ask them to sit with you for a moment and then tell them calmly and explain how bad it can be for them if they keep doing this.
You should show care and compassion, and they might understand what you are trying to do. If they accept it and change, that's well and good, but if they don't, as I said earlier, there is nothing much you can do in that case because they are grown ups, and you can't forcefully stop them from doing something.