Hopefully you slept well and when you read this you'll be in higher spirits.
I wouldn't say you're depressed because you still want to pull yourself out of your situtation. First off, I don't understand the deal between your brother and you but you shouldn't have to give him all your pay. Obviously you're entitled to keep some of it, for yourself and obviously you should give him some since he lets you stay with him.
You're basically suffering from lack of motivation. And the reason for that is because you're not getting proper rest and over stressing. It can happen to anyone, really. The only thing I can see is that you're in a situation that you're feeling helpless in, but the point is, you're just feeling helpless, you're not helpless. Too much coffee will also depress you. One thing, ditch the caffeine in your life, you'll feel better. An apple can give you the same boost that coffee can, but without any depressing side effects (infact, a cold apple will make you feel pretty happy..). Try that.
I can totally understand how difficult it is to put college + work and then try and get good grades. It can be a monumental task so don't blame yourself for not being able to achieve it, you have other stress factors pushing you down.
About the academic scholarship, if you want to continue with college you might want to start looking in for other financial options.
Get some exercise, you'll feel like you can do more in life. It'll give you a nice shot of testosterone in your blood stream and you'll feel re-energised.
Do stuff that makes you happy, listen to a lot of music spend a lot time with your guitar.
First you need to feel happy, only then will your productivity level rise. You're already overstressed and that'll keep you from trying to make yourself happy. (OMG! I have no time to do happy stuff, so much on my mind, so much to do..I'm in such a situation..). That's a thought you have to avoid. Don't let that pull you back. Go see a movie, get some fresh air, go for a walk in the evening or for a jog. Go see a beautiful sunrise/sunset. Basically pull yourself out of that rut and get going. The motivation will come automatically. First you need a sense of well being.
If you don't feel like talking to your brother about it right now, don't. Talk to your college people about your difficulties and how your mother cannot come and if there's ANY other option. You'll find a way, just need the will : ).
I know it's not that easy, but you gotta start somewhere and I suggest you start by making yourself happy by doing things you like, the rest will follow.
