It's hard to speculate about the future but if you guys are all so young, try to think about it from a 20-years from now perspective. From someone with a few more miles on the tires as you, I agree with the posters who say that you should split it three ways and put theirs into an account.
Be careful of people who say things like, "Legally, you are entitled..." when they may not be an attorney or even an attorney in this field. That is irresponsible advice and may not be true. I'm not saying that you should hire an attorney. And, just because something is "legal" does not make it "just" or "fair".
How will the B. of 20 years from now feel about this decision that you only have one chance to make? It may or may not be a ton of money and you may have really good uses for it but something about your post makes me sense that you wish for some sort of reconciliation - even if it is years from now. It doesn't sound like any of you have had the easiest of lives.
They may be making horrible choices right now in their 20s but that doesn't mean as 40 year old men that they will still be acting this way. It's hard to have compassion but I sense from your post that you do. What if this money could be the jumpstart they need to get an apartment, find a job and get on the right track, would you wish that you could give that to them?