Would you accept a kidney donation from someone you knew, but not family or close friend?

First, here is some background:

I have a relative (in his 60's) who needs a kidney. He's on dialysis and is doing ok. His wife, who doesn't match his blood type, has signed up to do a kidney swap. For those not familiar with a kidney swap, this is where one person exchanges kidneys with another donor/recipient pair. Two live donor transplants would occur. This will help him get a kidney sooner than waiting for an anonymous donor.

So here is where the story gets odd. An old friend of my relative (he hasn't talked to him in about 40 years) runs into him at a high school reunion. They get to chatting and the kidney issue comes up. The friend says that he's the same blood type and that he'd be happy to donate his kidney. My relative didn't think this guy was serious, but the guy called him up later that week to discuss it, and he's since gone and been tested, and is close to being cleared to donate.

This almost seems too good to be true. Here is my concern. What happens later on if the donor is out on his luck and needs help (financially or other). There seems to be a risk that he could take advantage of my relative, and he may feel compelled to help him. The donor seems like a good guy, and should be well off, since he's a pharmacist.

What would you do in this situation? Take a kidney ASAP from the old friend and hope you don't get taken advantage of, or wait for the kidney swap process to find a match, which could take a year or maybe longer?

TLDR
A relative of mine needs a kidney
Old friend that he hasn't seen in 40 years wants to donate
I'm worried that said friend may take advantage of relative.
Would you take the friend's kidney or wait for an anonymous donor (through a kidney swap with wife).