we will be signing a band member agreement which indicates the following:
band entity is owned by the band manager
So the manager owns the band, not the members.
songs written by the band remain property of the band.
But the manager owns the band entity, right? Presumably meaning she can hire and fire members. So if your son contributes to writing a song, he doesn't retain any rights in the song because it belongs to the manager, and if he quits or they fire him he doesn't have rights to anything.
complete songs written by a band member remain the band members ownership
All right, an admission here of a way for your son to remain owner of a song - if he writes the whole thing. Here I would raise a question; what exactly constitutes "writing a whole song?" Does he need to compose every element of it, every drumbeat and hit of a snare? My understanding is that in law "writing a song" generally means just lyrics and melodies. I would make sure that's explicit, otherwise he may find this clause denying him ownership because the drummer played a beat your son didn't write out.
Also, there is the practical matter - what assurance is there that the band will actually record and sell songs your son composes? I can see that in theory it's good that he would own whatever he writes, but in practice, since the band is so clearly the manager's project, management has no incentive to promote anything he writes.
money earned from gigs will be placed in a fund for operating cost
Wait, what? So your son is expected to play paying gigs, but instead of getting paid for them, give the money to the manager?
manager agreement: manager gets 10% commission only for work obtained by band manager where the band or members represent the band.
the agreement does not apply for work obtained by the band member not related to the band or work not obtained by the manager
Well, I'm glad the manager isn't laying claim to money they had nothing to do with earning, that aren't even part of this project. But I don't get the 10% commission, because the prior clause you mentioned said that all the band's gig money goes to the band fund for "operating expenses." So based on what you've told us, if the band gets a paying gig, the manager gets 10% for themselves, the "operating expenses" get the rest, and the band members get nothing.
the wording seems pretty straight forward. It appears they are trying to be on the up and up. If anything in the language seems bothersome please let me know!
OK, since you're abbreviating the agreement to post on a forum, maybe you've left something out. Based on the points you mentioned here, this looks like one of those lousy exploitative contracts you often hear musicians complain about. If there are any other clauses in the agreement that actually protect band members' interests or provide for how they get paid, I'd like to hear it.