I never thought I'd say this, but write him a check and give it to him the day you depart.
a) neither of you should be in possession of that much cash... if you're uncomfortable with loads of cash, shouldn't he be as well?
b) he can e-deposit it on his phone to his bank anytime he wishes and withdraw as he sees fit.
c) if you're doing a trip like this, there better be mutual trust and if so, all will be fine, right?
d) OR, text him and ask him how HE thinks the fee should be handled.