Thank you for taking care of this dog, He is a sweet looking dog, From the photo he looks like a poodle mix, however your vet will be able to give you a better idea of what breed he is when he does a hands on exam, as he can see the whole dog, size and physique, which is not visible on the photo The same is with estimated age. The vet will also look at his teeth and will be able to tell you whether it is a young dog or an older one , and may be able to pinpoint an age range. If you cannot find out whether he was vaccinated, you can have him vaccinated and wormed at your vet. You may want to give him a bath and a brush before taking him to the vet, so he is presentable and it will be easier to examine him. Again, thank you for saving this little fellow.