Re: Friend was babysitting when baby stop breathing in her care
First of all, I'm not sure the baby had SIDS. From what I was taught, there is absolutely no chance of resusitating a baby who stops breathing because of SIDS.
But as far as comforting your friend, you might do some research on coping with stress. It might help your friend to know what some of the normal reactions are in very stressful situations, and what some good ways to cope are. For example, it is normal to feel guilt, anger, relief (that it wasn't her child), to have difficulty sleeping, to lose interest in normal activies for a while, to have difficult eating, to cry for no apparent reason...I'm sure there's several more that I'm forgetting. Some good ways for her to cope are not changing her daily routine (as much as possible), exercising, even if it's just going for a walk, eating healthy foods, and talking with someone who is willing to listen. It might also help to reassure her that as long is she finds ways to cope with her feelings, they will decrease or go away with time.
You might be able to comfort her better if you find out what actually is wrong with the baby. It's probable that whatever happened would have happened to the baby at some point, and unfortunately, it just happened to occur while it was in her care.