I"m sorry to tell you that there is no way to know. A doctor who has all your medical records might be able to hazard a guess. But the truth is that even for a doc it will still be a guessing game.
Why won't you go on dialysis? I felt that way about 15 years ago. I eventually did go on dialysis (I have a strong will to live) and it wasn't anywhere near as bad or horrifying as I though. I was on for a year, got a kidney from a cousin I barely knew, and it has been successfur ever since.
There is hope - you should think about it. There are several different ways to do dialysis and it can be quite easy to do without requiring you to spend 4 hours in a chair at a center.
To be honest, they hadn't adopted the "stages" yet when I was at that point. I think my creatinine was probably around 300 (about 3.5) when I needed the calcium from the tums.
I am never 100% convinced of how much these things will actually affect a kidney. I suspect that part of the issue is that it hasn't been extensively studied yet. I always trusted my neph that a drug wouldn't hurt me (at least not too much). Sometimes it's a necessary trade off. I used to take a bit of Advil when I had my periods due to monster pain. It wasn't good for my kidney, but I couldn't function otherwise.
Just like with diabetes there is no one size fits all diet when you have kidney issues. What he can and cannot eat will be based on what his blood levels of various things are. Seeing a renal dietitian will help. If it is a choice between the diabetic diet and the renal one, you are best to choose the renal one because you can get into more trouble if you don't follow it. Is he on insulin? Getting the books "Using Insulin" and "Think Like a Pancreas" will help.
As for not matching - they have ways around that now. Have you ever heard of something called a paired donation? It's pretty cool. You want to give to your husband. But you don't match. Someone else wants to give to their spouse. But they don't match. What they will do is find you a good couple to pair up with. You donate to the other couple, and their donor gives to your husband. Isn't that amazing? It can be extended to chains too. Donor A gives to Receipient B, Donor B gives to Recipient C, and donor C gives to Recipient A. I think the larges chain had 20 or so couples.
It is better to get a transplant before dialysis. Dialysis only does a small percentage of kidney function. Enough to stay alive, but not always enough to keep you feeling good. You feel much better with transplant and live longer and are healthier.
The good news is that your husband can live a long time. I had protein in my urine when I was about 14. Went on dialysis when I was 38, had a transplant at 39, and am now almost 50. So things can work out.
With proper care (diabetes and bp control, diet, etc) it can take a very long time to get from stage 3 though to stage 5 and then ESRD (end stage renal disease). I think it took me about 10 years. Some folks go faster, and some progress slower. The important thing is to keep in mind that life is not over. You can continue to do well even with kidney problems. Has he seen a nephrologist and the team including a renal dietitian? Diet plays an important role at this point as does glucose control.
Find out about the diet required (this will be based on his labwork) and help him follow it. Try to be positive. Are you thinking of donating to him?
Some of it does depend on luck. I had a couple of anasthetics while in that stage of kidney disease. They were very careful to keep me hydrated before and after and I had no effects on my kidneys. But it can happen. So you Mom will have to decide if the comfort from the knee replacement is worth the risk of maybe being pushed onto dialysis. Has she made plans already? It might be the time to decide what to do, just in case.
First off, because her kidneys are not working, she needs to avoid salt. Too high a level which can build up can affect her heart even more.
When you say she could not urinate, did you mean that she could not void her bladder? Or did you mean that she did not produce any urine? Not producing urine is part of having kidney failure. The organs do not work and therefore do not produce urine. If she can't void, that is a different issue adn could be due to several things including diabetes (nerve damage).
Has she spoken with a renal dietitian? There will be certain dietary restrictions now that she is on dialysis and these must be followed or she could be in significant danger.
As my husband always says, on the internet, no one knows you are a dog. How do you know that there is a legitimate doc on the other end? It could be someone trolling for into with a medical textbook or access to google.
If you are in ESRD you should have your own nephrologist team to tell you what is going on. What option of dialysis have you chosen? Do you have someone who can donate a kidney?
Sorry, but internet medicine is a dangerous thing. We can give you some personal info given our experiences if you have question.