Yep, my family did it to me. Borrowed thousands, of which I didn't make them repay. When one finally went bust, I refused. Then, I was told that I was materialistic and worldly for not giving. Meanwhile, they didn't know/realize the thousands I gave in the past to other JW(ish) family members that I felt were truly in need. I told them, and then they tried to shut me down for other things, "You'd be nothing without your spouse . . . " And, that's when I cut them off from me.
My suggestion for you is to play poor. Talk of impending layoffs. Offer them only $100 to cover food & gas for the week, but you can't give anymore. You are going to have to live a double life.
It would be easier to give if they were truly in need (not able to work). But, those who are offered jobs and don't take them, or those with money that choose to spend unwisely, can't be helped