My old man's heath is declining and im scared.

This is my old man speedy. Photos taken in September, He turned 15 in June/july. He was a rescue as a pup in 2010, my grandma got him for us for Christmas that year. In the last month he's eyes got blue. He's hips give out and he's always panting. Today feels like the worse day ever. He can't open his eyes much. He's sleeping all day. He didn't even get up for food but I brought his food to him and he ate it. I had to hold him up. I put him out on the grass and he just layed down. I don't want to loose him. I'm going to try and schedule a vet for next week. I tried this week but they don't have any openings till next week. December is busy for work so idk when I'll get time off. I love him so much and it hurts me to see him hurting. I haven't told anyone apart from my mum who I live with. I don't wanna worry anyone but I'm really struggling.