Codependency Support Group
Codependency is defined as someone who exhibits too much, and often inappropriate, caring for another person's struggles. A codependent person may try to change, or feel shame about their most private thoughts and feelings if they conflict with the other person's struggles. If you are on a journey towards self-love, this support group is for you. Join us and find others...

Also we have to learn to speak up and directly communicate what we need from others. In the car home maybe you could have said "hey a-holes how about grabbing some food since I'm temporarily crippled and may starve to death." Okay, that was an exageration but you understand what I'm saying.
Same thing with the suitcase "hey would you mind helping me with this?" The key here for all of us is to ask for help when we need it.
I have a similar situation with my brother and sister in law.. been going on for lilke 40 years now hahahah rofl...
When I had cancer like 16 years ago I had to ask my brother to come stay with me while I had this chemo that would either kill me or cure me.. He whined about coming to be with him and I said "look... I am sorry I have to ask you to come but this will either cure me or kill me and I need my next of kin to be with me in case I die... you are my next if kin.. "... he came and had a pretty good attitude.. but listen he don't get it.. still doesn't get it.
Now I love my brother.. even if I feel he gives me no support.. but.. it is the way it is.. for what ever reason (I strongly suspect sister in law has something to do with it)...
So.. ask for what you need from them.. and thank them if they come through and move on if they don't that is all you can do.. and try not to blow up at them because it will only make you look like a psycho ;) ...
Hugs