Legal advice: involved guns, drugs, and wrong people being blamed.?

I'll start in the beginning. During high school, there was this guy I'll refer to as Mr. Nice. It's what he called himself ______ Nice. I knew this guy since middle school and we were close friends. During high school freshman and sophomore year, this kid changed. I know what type of person he always was. Kind of a nerd, loves video games, a real crowd pleasing kid. In high school he started dealing weed, which in my area almost every kid has been dealing. Not saying he was good because he got caught three times. The first time was in sophomore or junior year (I forget). Nice straight up got ratted on (not that I care) by some kids that was in the same operation as he was.

He got kicked out of school and moved to a town right next to ours. THERE, he started going a little heavier on the drug dealing. Nice also had lots of people coming in and out. Lots of other drugs involved like x, shrooms and acid. So the first time he screwed over his friends was me. I was stupid and young back then. I got a little involved and I was done afterwards. During the time I was involved, there was a huge conflict between me and Nice because of him trying to rip me off, etc etc. I was over with this kid and I told all his friends (who were also my friends) to be careful. This guy is a schemer and he doesn't care if you're a friend or a stranger.

In a little while (our first year of college), a friend I met in class was also friends with him. I will call him Ranger because he's in the army going through training atm. So Ranger is persuaded by Nice to buy an automatic rifle. I have no clue WHY he did. I don't know HOW he was persuaded (because Ranger is a good guy and he's always been a good kid). Ranger goes and buys this stuff for him.

A little later, Nice moved in with my brothers' friend I will call Collie because he has a border collie. Collie has his own store right below his apartment and was working that night. I guess Nice was having a party or something and (not too sure on what happened) the fire department came. The fire department found close to 5 pounds of weed and that assault rifle. One of the guys is a volunteer and he is a police officer. He finds all that, and since the apartment is under Collie's name, he gets charged with it all AND money laundering even though it was a legitimate business and Collie had nothing to do with it.

***Now, the legal advice part comes here***

So Ranger is training and proudly enlisted in the Army. Now undergoing Ranger training. He's matured a whole lot since then and doesn't do anything stupid. Since then, Nice said he will fess up to what happened in Collie's apartment as Collie himself served jail time for a few days before getting a bond deal. Nice never did. Nice is currently going to a nice college right now. Collie is running his business, and Ranger is enlisted. The whole ordeal was traced back to Ranger, of course. Now he's being questioned by the police officer there. Can you tell me any kind of legal advice to put Nice where he belongs? He screwed over 3 of his closest buddies that knew each other for years. But all in all, this is for my friend Ranger. He's the one who'll probably face the worst part of this for the very fact that the rifle was purchased by him. I haven't spoken to Nice in quite a while but I know the kid is still around and still hanging out with some of my friends (whom I pretty much disassociated myself with for getting involved with that POS). Anyways, what can we do to minimize or null any punishments for Ranger... and what can we do to get Nice where he belongs?