I'm preparing for the worst

My son's dog, Bo, an eight year old rottie, has bone cancer and his quality of life is fading. Right now though, he's not in much pain since he is on pain meds. He still eats well, and barks at our other dogs while guarding his bowl. The cancer is in his left front leg with a tumor in that shoulder. It has started to have lesions that leak. I know that's a terrible description, sorry. He does get around though, going outside to lay on his bed and then barks at the door when he wants to come back inside the house.

I know we will soon have to euthanize him. That just breaks my heart but I know we can't let him suffer. I was reading a post about a memorial plague and saw an urn with a picture of the pet etched in stone. I didn't realize dogs can be cremated. How do I go about finding more information about that?