My Dod is very old and i have to leave...

Hi there...to increase the longevity of our pets it's important to have them evaluated by a veterinarian annually to learn if their are any pre-existing conditions that need to be treated immediately. Good qualiyt diet is crucial for senior pets so find foods that are devoid of byproducts and high carbs (e.g corn, corn meal) because kidneys have a more difficult time processing grains fillers which are used to lower the cost of manufacturing of pet foods as well as bind the dry kibble together. Canned foods are easier to digest and helps the urinary/kidney function more optimally as well. Dry foods are responsible for making urine more allkaline because urine needs to be acidified in order to prevent urinary/kidney decline--like cranberry juice does for human bladders/kidneys.

is there in your country have a Society for Prvention and Cruelty like ASPCA (in United States) ? if there is, just let your dog to them to carrying him ... or maybe somebody who want to addopt him for you ... :)

Theres no tricks in prolonging a dogs life. We can never say what might happen during the 2 years that you will be away. The best you can do for your dog is to leave him to a person that will take care of him just like the way you do.