I started treating my dog, and it turned out he has stage three kidney failure and seizures, the cau…

I started treating my dog, and it turned out he has stage three kidney failure and seizures, the cause of which no one knows. I admitted him to the hospital, first to one, then we went to a nephrologist and transferred him to another. On the first day, he had a seizure and cardiac arrest, but they revived him. I visited him today; he's lethargic. I wanted to take him for a walk, but maybe his blood pressure is low from the IV fluids, and he doesn't want to walk. I picked him up, but he refuses food, drinks little, and urinates little. His blood work today isn't great. They say he's unstable, his tests aren't good, and no one knows how much time he has left. They insist he should be hospitalized for two weeks, which is very expensive. Today, he even fell asleep on the chair next to me, resting his muzzle. How can I euthanize him? He's unstable and could go at any moment, but he's not in pain. They said if I take him home, they'll give me a treatment plan: injections to support his kidneys, painkillers, and heart medication. I can't bring myself to euthanize him, and I could take him home, but what if he dies in front of my child? How will my child react? What if it deeply affects their psyche? I'm just full of doubts. My mom said to leave him there to be euthanized. A friend would take him home. I have no one else to consult. This dog is deeply loved by me; we've been together for 13.5 years. I'm his whole world. He even whimpered when I left; he's just my mama's boy. My heart is breaking 💔. I've been living these days with hope.