My boyfriend is putting his dog down tomorrow. As his girlfriend, what can I do to help him during this tough time?

My boyfriend's dog, Yukon, is 16 years old. He is half husky and half chow chow (imagine an extremely hairy husky). Through out the 2 years I've been with my boyfriend, Yukon has been developing a walking problem. We have done everything we could to help him (giving him aspirin, fencing him downstairs, ect.). However, regardless of our efforts, his condition has been getting worse. It has gotten to the point where he has given up on walking all together.

My boyfriend loves his dog like a brother. He has never gone through losing a loved one before in his life, so I can't help but worry about him. Initially, he wanted to go by himself to put his dog down. I asked him if I could at least drive him there, and he agreed.

My boyfriend has never been the kind of person to cry. Since this difficult decision, he has broken down multiple times. Please, Reddit, I want to help him out during this rough time. Any suggestions on how I can help him cope with his loss?

And also, any ideas on what we should do for his dog? It will be his last day and I think we should do something special for him (give him steak or something). Please give us some creative ideas we can do for this wonderful dog and friend. Please and Thank You!