Very bad news...

So mom told me that they're thinking about putting Buddy down.
His leg is badly hurt. He can still get up and walk but he limps most of the time and he trips and fall downs sometime. He has trouble lying down and he can't sit anymore. When he wants to lay down he sort of shakily lowers down and then falls down abruptly.
He used to had trouble going up and down the stairs. He would fall down the stairs that went down the basement. He hasn't go down those stairs in over a year and theres the stairs that leads to the backyard from the kitchen. He could go down there fine but when he's in a rush he would fall down. Now he's careful when he walks down the porch steps.
Getting up is difficult too. And when he has to go relief himself he can't make it to the door sometimes and leaves the a mess on his way to the door. Or when he's been lying down for a long time he just poops and just move away from that spot. He doesn't pee in the house at least.
Now we could have just leave him outside all the time however he barks a lot especially at night and that annoys the neighbors. We had calls of complaints before and they even got the police to knock on the doors.
Sometimes I wonder if he's in pain but he still asks fine. And still acts energetic when he wants food, go for a walk around the block or greet visitors.
But I don't want him to go...I wish we had the money to pay for his operation but it was too expensive and its too late now. The only thing we could do is get his leg amputated but I don't think he could adapt to living with three legs and there's walking up and down the stairs
Some might say its better to put him down because he's going to get worse. I knew he had to be put down if he didn't pass away naturally but I still want him to live longer....
This is breaking my heart...I love him very much and I can't imagine not having him around anymore....