I would suggest getting to the bottom of exactly what happened. You have to approach your grandfather in a very non-threatening, non-judgmental way. My aunt did commit suicide and it is not an easy thing to deal with. I don't know you, or your family situation but it is something that you will never fully get over or know "how" to deal with. It's something that goes beyond fully comprehending. I would say that he has more issues than just his sons arguing, accusations. Generally there is something that goes a little deeper than what meets the eye. Good luck, I hope your grandfather realizes from this experience that he truly does have people who care about him and how many people would be affected by him taking his own life. I would definately have someone nearby him for a while, if I am not mistaken the statistics show that most people who attempt suicide unsuccessfully usually try again.