What does it mean when someone is convenced to commit suicide and what level of accountability do they have?

A 21 year old college student is said to have contributed to her boyfriends suicide on the day of his graduation.

I never want to see another Mountain Dew in my life!!

In my moment of desperation ate what could only be described as a diabetic cocktail which resulted in me spending time in a port-a-potty and driving 54 miles half alert to my bed.