[ Jack does keep up with him, he stays close, worry lining his youthful face. His family hasn't gotten drunk in front of him before, not even the two who actively can if they want to. It feels strange to be the one who has it together, not the one that everyone's constantly worried is going to fall apart. He has a lot more reason to be concerned that's happening to Castiel at the moment. ]

I think we both know that I can do it better than you right now. Maybe let's move to one of the pool chairs? You need to lie down.

[ Jack doesn't know anything about first aid, but he figures that Castiel moving around gives him more reason to fall over and get hurt some more. He's not exactly moving in a way that fills him with confidence that this is the best option for him. ]

I'm sorry I've added to your struggles, but I'm also here for you, you're my family. And before you say I'm not, you said yourself, I'm your nephew. We are family.