My grandparents are the same way: They HATE all of my snakes, and they tell me when the snakes get larger they will strangle me and if I sleep with them they will strangle me when I'm asleep.

I can't convince them to respect snakes, not one bit. They want nothing to do with snakes, and they don't even want to come in my room even though my snakes are in cages and cannot escape. Since they live at their own place, I won't worry about telling them that snakes aren't evil because I don't live with them so they can't say anything or make me get rid of them.

Now, the best way I think you should do this would be to tell him interesting facts. But first, get him to listen, and if he ignores tell him that you are serious and you WANT him to listen. Tell him the positive side of snakes. This helps over power the negative things they have heard, so that is why they think snakes are evil and mean and all they want to do is kill people. Tell him why snakes are good to have around, and when you are explaining to him, have one of your nicest snakes in hand with you so he sees that all snakes aren't bad. I helped a 8 y/o become not scared of snakes by having her look at and handle my nicest snake, which you know is Candice. Good luck with this, and hope you are able to convince him that snakes aren't all mean.