A handshake agreement (not written down) can definitely hold up in court so be careful in not giving any claim you are owed through your claiming of money as it could represent your giving up your potential equity as well.
Doesn't matter if he has an LLC, you may likely have claim if he was not clear that you were not receiving equity (i.e. such as if you were coming in as a contractor).
http://www.backofanapkin.co.nz/ is a brilliant idea for this sort of pre-company-formation thing -- at a minimum it forces you to spend a few minutes thinking about what happens if things don't work out in a team/project/idea.
Doesn't matter if he has an LLC, you may likely have claim if he was not clear that you were not receiving equity (i.e. such as if you were coming in as a contractor).