[X] To decline his offer. You did it for both of you, and Yamato did most of the work. He owes you nothing. (Gain Bond: Buddies, +6 Relationship Points)
[X] To take him up on it. It's his way of paying you back. Why turn him down? (Gain 1 Favor from Hose (Favors can be used to call someone when they're busy or for help if you don't have a high enough Relationship Rank. However, it could cause complication depending on when it's called in), +3 Relationship Points)
[X] To let him know that, if he owes anyone, it's your brother. Yamato did most of the work, and you wouldn't have gotten this far without him. If feels like he has a debt to pay, it's to him, not you. (Yamato Gains 1 Favor from Hose, Yamato gains a Relationship With Hose)