So I ask, did the friend do well in returning $10 to his friend or the returned $10 was not enough?
He do not want to lose then why did he gamble? Or let me say he do not want to lose 30% of the $190, then why did he gamble with the 30%. 30% of $190 is $57. He could have just gambled with $133 or lesser than that. If he won his friend, what tendency that he will even give the $10 back? No tendency. I will prefer not to gamble with a friend but if I did, I will not give him even 1 cent back.
What is need to gamble if he haven't made up his mind to lose, the friend is so kind to have given that $10 at the end of the day, the question he should have asked is, if he had gamble in an online casinos or physical casino will he have hard the option of getting a tip after he have lost?
Best thing for him is to just walk away and be thankful to the friend that won his money that is willing to give him some tp at least he will have some left over to gamble again or save as pocket money and bear the pain until he is recovered and learnt the lesson never to gamble with an amount he can't afford to lose.