Tears for you and your baby are in my eyes right now as I type. We are so very very sorry for your news, and send lots of hugs and prayers and puppy kisses to you and Gus.....follow your heart...it sounds like you know what to do...just treat him as you would want yourself treated and love him with all your heart. The wonderful and magical thing about boxers is they take up residence in your heart and will always be a part of you.....I have no good advice for you, just lots of heartfelt sympathy. You sound like a wonderful and loving boxer parent and you will make the right decisions for him....again, very very sorry for your news...
Hug, prayers, and puppy kisses,
"Momma Dog" Titan and Jasi