I certainly don't feel as though he's obligated to give me anything since I'm an adult.

It's like you said, it has to do with the promise.

And it most certainly is because he didn't expect me to come up with the money so quickly.

The worst part of it is that I watch him blow all the money he got.

Before he got the inheritance last February he was broke. He's disabled and can't work, but he can't collect disability (long story why he can't). He did manage to find an easy under the table job that was part time and that's what he lived off. A friend lets him live in a small basement room for $50 a week.

Now, one year after getting $350k he's done nothing to change his life.

He still lives in that shitty little basement room with nothing a but a mattress on the floor, a nightstand, and one chair (though there is now a $2k giant 4k smart TV in there as well).

He spends almost all day sitting in a bar room drinking. He has no qualms about buying multiple rounds a day for his buddies.

He smokes 2 packs of a cigarettes a day.

With the smoking and drinking alone he's blowing through close to $100 a day.

All he does is complain about how miserable he is and how his life sucks.

When he first was about to get the inheritance he promised my sister and I $10k each out of it to help us out. Once he got it, he never brought that up again.

Granted, last spring he paid $1k for me to get my car fixed, and give my sister $3k for her wedding.

So he's not totally selfish with the money.

I know I'm not entitled to the money, but to see him blow through what I need now every single 10 days or so really pisses me off.