I always thought the songwriter gets the most money. Or should. Didn't Jeff write alot of the music? But if there was already a pre-made contract that they follow then I guess that doesn't count.
I've had to deal with this a lot recently (i'm officially over trying to do anything in a band as even REMOTELY a source of income, all dreams crushed, now just full on hobby and i'm so much fucking happier to be able to do what i want without dealing with rockstars/egos/money) and the way it generally works is everyone who contributes to the song gets a small portion.
there's music and lyrics, so lets say for example billy writes the lyrics, joey writes the guitar and instrumentation. joey and billy both get 50%, everyone else gets nothing (this is copyright law mind you, any band where they have an agreement could be whatever they decide and which is why if someone is in a band for a career they need an agreement in writing for sure unless they want to deal with ridiculous shit eventually). however lets say that billy the singer writes the lyrics, joey the guitarist writes the guitars/instrumentation and then the bassist jamal writes some of the guitar riffs, now jamal is in the deal. so that's 33% for each of them.
the way it generally works for copyright is that anyone who contributes to a song, no matter how great or small, becomes a joint owner and gets a share of the profits, but not full control over the intellectual rights etc (for example someone who wrote one riff can't bar them from using it in a commercial for tampons, but will get money out of it). so they like to have everyone become joint authors so that it's pretty easy to divy up and there's not debates about how small of a part someone wrote or how big, because that could get a bit crazy though the only downside is lets say you have a falling out and you wrote most of the lyrics, most of the riffs, and the guitarist and vocalist wrote only some, they still get an equal share of the money too, which would screw a career musician a bit. the drummer or people who didn't write any melodies/lyrics don't get anything from the royalties, but they can get hired as a performer and then they get some money, or they could have a copyright over the sound recording etc an dthey'd get money from a licensing deal or something.
tl;dr the music business fucking sucks, money in bands fucking sucks, and all of that sucks the passion out of everything and destroys friends if any one member/person decides to change/be a dick.