1. I don't think he did. We know from Bellatrix that he is always trying to get out of doing 'real Death Eater stuff'. Since she has only been out of Azkaban for a year now, so one could assume she was referring to Voldemort's first rein of terror.Originally Posted by bertiebott12
2. I think the fact that Severus constantly supressed his emotions made him a perfect candidate for Occlumacy. I think he may have been doing it naturally before Dumbledore taught him that it was a branch of magic and he perfected it.
3.I think the Lighting Struck Tower tells us perfectly, Severus was very emotional after he killed Dumbledore. So much so that I fear for his saftey, unless he can get those emotions under control before meeting up with Voldemort.
Anyway, it is interesting to note that Severus doesn't get emotional until Harry calls him a coward for killing Dumbledore, so I think that yes, he would get overly emotional if someone he knew was killed.