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?
Your friend is clearly showing an addiction problem because no sane person will bet an amount that he earn for a long time. That’s beyond responsible gambling already that needs immediate attention.
Most of this person based on my experience got angry whenever they hear an advice. Unless he is the one who voluntarily ask for the advice then that’s fine but forcing your own opinion even the intention is to help sometimes view by this person as negative.
I will try to evaluate first and based on that my actions whether I will confront him about his problem or not.