death by inner pain

in 2002 I lost my sister in law to sadness and stupidity and maybe even a planned suicide.  She was very sad.  Her life was very emotionally painful.  She went in the hospital for coronary bypass.  We all know the rule about not eating or drinking after midnight.  She smoked three cigarettes drank a cup of coffee. An hour before surgery.  She also took her nightly does of medication.  No medication was supposed to be taken after midnight.  Consequently during her surgery she bled to death.
In 2005 my brother-in-law Jim died of a massive heart attack due to alcoholism.  He was in a 45 day treatment program for his drinking.  But the minute he return from the hospital he began drinking again.
both of these relatives suffered great inner paint but neither ask for help.  My question is why didn't they just take a gun and shoot themselves.  Didn't they realize they were committing suicide.  Anyone reading this please tell someone you are in pain before you make up your  mind.
Jim left a wife and two children under four.  My sister-in-law left an entire loving family