RIP Riley, my beautiful Golden boy

[Hypancistrus]

Back in May I posted a thread about our Golden Retriever, Riley, who was diagnosed with a spindle cell tumor on his hip. We had it removed and the vet was positive that clean edges were obtained and said it shouldn't trouble him further. As part of the prep work for the surgery they did full x-rays and an ultrasound of his abdomen and found no cancer in his body.

Much to our surprise, we came home from dinner Friday night and found that Riley couldn't walk well and his stomach was very distended. We rushed him to our vet (luckily she was on night shift all week) and she immediately did xrays, thinking that he had gastric torsion. The xrays revealed that he had an aggressive form of cancer inside his body, on his spleen and all over his lungs. She said there was nothing they could do for him that would work at this late stage, with a cancer so aggressive that it spread that far and fast, in five months. So we made the difficult decision to put him to sleep. My fiance and I laid with him while he passed.

We are both devastated. We had gotten a new puppy, a papillon in early September to keep our Chihuahua company, and we are blessed to have her. She and the chihuahua have become great buddies and play together often. Apache, the chihuahua, seemed fine on Friday night. But last night he seemed to become very depressed. He keeps moping around the house and while he still plays and eats, he doesn't do so with his usual gusto. He's very subdued. I think that he is grieving Riley's loss and I don't know how to help him, especially when the pain of the loss is still so fresh and raw with my fiance and I. We spent so much time crying yesterday I think the sea level may have rose a bit from our tears...

Does anyone have any suggestions for how to help a grieving dog heal?