Is he a who or a that?

After much debate and a little research, I have decided that Luigi, Bailey, and Corky are all whos as opposed to thats. They are named individuals who have unique personalities. The Society for the Promotion of Good Grammar agrees. Therefore, I am rejecting the suggestion given by so many who proof-read my vet school application to refer to Corky as that. He was the first dog who captured my heart, who loyally defended me for 11 years, and who perhaps initiated my interest in veterinary medicine. Grammar police do as you will.