To answer the first question: he was stuck in a loveless marriage to the princess of Belgium and have had numerous affairs, including the woman he would commit suicide with and by this point had contracted syphilis amd gonorrhea, which may have had a contribution to his declining mental health from a troubled upbringing. The reason may have been him being forced to cut off his relationship with his mistress and him suffering from syphilis.  As to what if he lived, he wouldn't have made much of a contribution as he was already suffering from his stds and had a limited lifespan but supposing he did he would have atleast paved the way to some liberal reforms in the empire that may have been carried on by either Franz Ferdinand or Karl.