DS1 is a very gentle kind loving boy, will always be the first for a cuddle etc. he puts up with a lot from DS2, he is at the hitting stage and quite often they bump heads etc. accidently obviously but in DS1's eyes, DS2 has hurt him.
DS2 was trying to grab something DS1 had, I don't think he actually meant to kick him as much as push him away with his foot but none the less he did kick him. Have sent DS1 to his room, do I come down hard or go in gently?