Is it normal to think he was not crazy

Seen a guy the other day he had a tattoo it was the number 333 on his arm not too big vertical on the inside of his arm toward his body the numbers were about a half an inch , the guy paid that's when I saw it, i didn't say speak of it to my co worker, in my mind I found that kinda perfect, that number it was as if I had seen it once before but I could not really place it any where. He had a black shirt on but I could tell he was built. Looked casual dark hair olive skin He took the shake he had bought walked out I thought he was gonna get in his truck instead he walked over to an old man who stands in the same spot everyday on the same stop light I never roll my window down when I stop there, he gave it to the old man they talked for about 15min it looked like and he came back to the parking lot got in his truck and left I thought that was odd. I told my mother about it after she picked me up she told me my grandpa ended up in a nut house and he used to write those numbers on the doors on the inside of the house he used to tell my grandma that it was to protect him from something, he wouldn't say what it was he was afraid, he was not allowed to speak of it is what she said not even to her, I went to leave him flowers today in the cementery guess what his plot number was? i turned around and walked out, those flowers look better on my table anyway. That's scary and He died at 79 years old. What does that number mean?