I just left you a post on your first question. I should have read this one first before answering. All threats of suicide have to be taken seriously. I don't know your father and I don't know what experiences he had in the USMC.
I don't know quite what to say but I think the most likely problem is that he is afraid you will die, it's that simple. And you are not likely to convince a former marine that there is not a chance you could be killed because there definitely is.
I have two not so great suggestions:
Go to see a counselor (maybe even the Marine recruiter) with your father and see if you two can come to some kind of agreement, or
Consider another service. How about Navy Seals? (They die sometimes too) or even Navy Seabees like me. Air Force and Army both have elite teams similar to Marines.
My father steered me to the Navy because he had good experiences with the Navy in WW II.
It was great advice for me. Maybe your father is pushing you away from Marines because his experience haunts him to this day.
Maybe your father is giving you good advice too. I hope you can come to an agreement. You have managed to insert yourself between your family and your country. I think you both have to compromise and come to an acceptable solution for both. Compromise is nothing new or to be ashamed of--all of us do it everyday. Best wishes in your decision.