Omg, sending love to you! My husband has a kidney transplant, so I totally get it.
Just wanted to say that in the absence of a match in the family, there also may be the option for you to donate a kidney to a third party, and for your husband to receive an unrelated matched kidney. Sounds like he does have potential family matches, though, which is excellent. Can any of the potential donor testing be done in the DR?
Btw, I don't usually recommend this, but in your case it might be good to contact your US senator/congressional rep for assistance. Especially given the time urgency.....and, they might be more willing to help because of the PR/human interest aspect.
Feel free to DM me if you want. My husband received a sibling's kidney >20 years ago, and is doing great - even got through a COVID infection unscathed. *Hugs*