Hi, can you talk to your vet and find out if there are any vet techs who might be able to stop by?
Can you register with Rover or Care. .com (actually registering, --as opposed to just google-ing and looking, provides more accurate information) so that you can see rates, skills, how many return customers a person has, reviews etc?
I am assuming that someone is going to be staying with the cat in order to make sure that he is fed and has freshwater. From what you are saying, however, it sounds as if that person is not able to give the insulin.
I’ve had two diabetic cat who were on insulin and I do need to tell you that not giving the insulin for a week could be very serious. Please check the suggestions that were given previously and see if any of them would work for you.
I also recommend letting your vet know that this could occur.