Thank you everyone, I am so heartbroken and my house is so quiet it feels empty!! I seriously think he was waiting to make sure his boxer brother wouldn't be lonely as we just purchased a new boxer puppy a couple weeks ago.
I also know that Gunner knew what was going on that day. Dually had passed about 5 minutes before I got home from work with my son holding him and petting him. As I was saying my final goodbyes and bawling my eyes out, Gunner came up and rested his head on top of both mine and Duallys.
I am very thankful that he passed at home with my son and husband by his side and also that I did not have to make that awful decision to take him in even though that was the original plan that day.
He will be dearly missed and always will hold a special place in my heart. There will never be another one like him!!