I think kishi wants to show us the 8th gate so that may happen
Yes, Because of the toll it takes on the body. It would literally destroy him from the inside out. Doesnt matter whos giving him the chakra. Too much strain on the body.
wouldnt work.....gates dont use chakra, they simply surpass the bodys natural limiters.....now it is possible that after the gates are used , kurama could heal gai with his chakra, but simply giving him chakra in the first place, would not do much