Hi there, it’s such an awful situation your stuck between a rock and a hard place. He’s very lucky to have you and he’s father managing he’s finances, it’s good he’s allowing you to do this. I would take him food now and again but would make it very clear it’s not going to be a weekly thing unfortunately it is enabling as anyway they can carry on the addiction without the consequences they will do. Unfortunately until he sees the damage or consequences for himself he will unlikely want to change.