He is brother was not smart enough to arrange his life properly before going to be a dad.
You are understanding this situation correctly, and I know what you are talking about. I would also get angry at my brother for him having to get money from my parents for his own needs while he did not have a job.
I think that probably your bro will change when he will face the responsibility for his child.
When you feel all alone and unhappy, turn to you Inner Child and talk to Him.
You will see He can comfort you like nothing else!