Advice needed

My son who is about to be 19 years old told me last night he is going to join the military. That he hates high school and is barely passing (which as much as hard I can be with was school work and it's his will but he chooses not to go to class or do the work) and he cannot do college so his best choice is going the military. I am not against it because I am glad that we have our children, cousin, aunt, uncle in the military and I am very proud of every single person but at this time with this crazy stuff going around I wish my son can see a better way for his life. I know as a person we support his decisions and I will stand by him but I cannot stop crying how can I deal with this when this world is fighting against each other. How can i be okay with this decision. I cried to sleep and I wake up to cry again. I pray that he will change his mind but as the end it's his choice.

At first he wanted to major in finance but now this.