Hello L..
As much as this situation with your brother, the uncle of your children, clearly upsets you, you cannot make someone change their behavior. What he is doing to you and your family is disresectful, hurtful, and unkind. It's okay to say that. But you cannot make him change. You can't chase him out of it, you can't love him out of it, you can't force him out of it. He controls his choice, and his behavior. So do You. You have done everything reasonable to reach out to him. Respect your boundaries. Stop pursuing. You know he will be back, he always comes back when he wants something. Have patience, wait for that moment, because you know it will happen. When it does, be kind and listen, but when he asks you for whatever it is he wants, tell him no. You aren't his back-up for when he can't do the job himself. Tell him the truth as you feel it: you don't think you can meet his needs because it makes you feel used that he only calls when he wants something. Stand your ground. He's had plenty of chances. He'll decide what he's going to do with your "no". If that's continue his current path, then it's sad, but it's his choice. I suspect he'll either resort to some coercive behavior to try to get what he wants (applying anger or guilt or threats) and disappear (trust that he Will be back), or he'll put some thought into it and decide to change. Either way, you have done right by you, and you and your family are free of the burden of your brother's irresponsibility.