The very best thing you can do for yourself, your child and your dysfunctional Mom and Bro, is acknowledge, accept and embrace that looking for support from your family, emotional, physical or financial is always going to end in disappointment. Stop looking to them for these things, they don’t have it to give!
Accept that you are on your own. Period. If you don’t want to stay embroiled in the problems of a couple of drug addicts to rule your world, then you need to put on your big girl panties and make your own way in life. Does it suck? Yes most certainly, but you know what sucks even more? The crushing disappointment of constantly being reminded how imbalanced their priorities have become. They value their own dysfunction and drug habits more highly than supporting you. This is not going to change, you need to accept that, in a way that demands more maturity than someone your age would usually possess. But you were a very young mother so that must have pushed your maturity somewhat ahead of your peers, I should think.
You need to achieve complete financial and emotional independence from both of them. The sooner you accept that the sooner your life will get better. You need to do for yourself. Go to a local church (no, you don’t have to be a member or a believer, and counselling service is free, and they will know all about resources you may not be aware of!)
You have not said as much but it would seem you feel more deserving of financial support that your Bro? You need to get over that, truly. Drug users don’t suddenly just see the unfairness of it all. And change their ways, no matters how righteous you feel you deserve it. Think really hard why you would look to a woman who thinks it’s okay to both buy and do heroine with her own son, for anything.
Believe it or not, you are much better off, no matter how much you struggle, than they are. They may well both be doomed, and may never be able to change the path they are on. You should face that reality. No matter how difficult the road ahead may look, if you step back from them, stop thinking they will change, and make your own way, you may look up a few years from now and recognize how you were actually the lucky one in your family!
Your priority should be protecting your child from these two, at all costs. What are you studying and how much longer do you have till you’re done? You said, “then I’d really have no one at all!” Honey, you are already there, except for your denial. Life will get a lot easier when you let go of the illusion that you ‘have’ them, and recognize the reality, that you ARE all on your own, and start living that truth instead of what you wish it was.
I wish you nothing but the very best of luck, i know it’s not an easy journey.