Seen Soundgarden in the mid 90's, after Cornells first divorce almost broke him when he cut off all his hair and sent it to his soon to be ex-wife at that time.
Sounds like he and his current wife were having marriage issues if she had someone "check on him". Something isn't feeling right in that last performance, he seems off that whole night. Chances are, he made the decision before the show started, and made several strange comments on facebook and the show.
This makes me angry and sad, this is a whole generation of lead singers that burned out too early. Depression and mental illness can be a funeral shroud.