maybe u shouldn't worry as long as ur friend knows wut to do and is comfortable around snakes they will be fine. Just call them if u feel worried. I'm sure your friend will do a great job u can right down instructions and give it to them so they know wut to do if anything goes wrong give them ur vets number and most of all don't worry and enjoy your trip!
Worrying won't do u any good
1.2 Corns, 0.1 Ball python, 0.1.2 crested gecko's and 0.0.1 Bearded dragon