So me and my friend were playing a THG and i noticed he had a {Firebreathing} in his hand. He uses a R/G while i was using a R/B deck. If he enchants my creature with that can he and/or i play the mana to buff my creature?
Having never played THG before, I'm just going to paste the rule.
810.5. With the exception of life total and poison counters, a team's resources (cards in hand, mana, and so on) are not shared in the Two-Headed Giant variant. Teammates may review each other's hands and discuss strategies at any time. Teammates can't manipulate each other's cards or permanents.
In other words, no you can't.
So he has to pay mana to buff mine..thats what i figured
Yep.