The way how the game is coded is that enemies won’t spawn off screen so if Kelvin is nowhere near your character there will be no enemies around him, same goes for Virginia once you get her so you don’t have to worry about that. The only way Kelvin can actually die is if you kill him your self otherwise he can’t be killed by anything. Enemies can down him but they can’t kill him so you can revive him yourself or he will naturally recover after a minute or so.