First of all, your parents should not be too partial, because all parents in the world are the same, they are all their own children, and there is no parent who doesn't want their children to be good.
Second, are you sure your father gave your brother that much money? When your brother is short of money in business, your father will certainly support him if he has money. If it were you, he would also support you.
Third, you must repay the gambling debt owed by your father. You have an obligation to help him, but you must find a way to do it.
Fourth, I suggest you get along well with your brother. If you two settle it through consultation, you are brothers and that is your father. It is impossible not to help him when he is in trouble. It also depends on how to help him and whether he has the ability to help. At this time, it's up to your brother. Because you have no money, the money mainly depends on your brother. Remember to discuss it with your brother.
Fifth, money is a foreign thing, so don't take it too seriously. Your brother's business should be relatively mature now, and you have just graduated and started, and you have to rely on his help. You can't and can't share the money your father owes with him.
That's basically it. There is no better suggestion. If you can't talk to your brother properly, or he doesn't take the money, then you'll have to wait for someone else to sue your father and let the court rebel against your family's property.