Bad day at my restaurant

Last night was just an awful night. I own a small little dinner and we had such a bad night last night. There's this boy named Eddie. He's 18. He's been working here since he was 15. He's such a great kid. The customers love him. He never gets upset even when he gets stiffed(not tipped). He's always been a ray of sunshine. Last night though when he came into work something was definitely off.... Everyone knows Eddie is such a happy person so for him to look so upset was unusual. We kept asking what was wrong and he said nothing. All night he seemed to keep getting more upset. He walkes into the kitchen saying "That's the second table that didn't tip me!" He's usually not like that. I decided when we slowed down I was gonna cut Eddie first. Cut means you close their section so they don't take anymore tables and can do side work. He obviously needed to go home because he looked like he was 3 seconds away from a break down. Then I hear this lady yelling at him about her steak not being cooked all the way. She called him stupid and he said "Fuck this! I'm done!" And threw his apron on the ground. My shift manager tried to call him down but he just said no I'm done. He was crying and threw his server book on the ground and said he doesn't even want his tips and he's done. I had my shift manager put his tips on am envelope for him. I called him this morning and told him there's obviously something going on and to take the weekend off and Monday to come talk to me and see if we can do anything to help. Stressful part and we are already understaffed and that's one less server for the weekend. Ugh thx for listening to me vent.