Unique situation- need advice

Hello! My fiance and I currently reside in Taiwan- he is a Taiwanese citizen and I am a U.S citizen.

We are going to get our marriage registered here in Taiwan next week, but I have a few questions regarding him visiting the US.

I want to preface- we do not want to move to the US. So I am unsure if immigrant visas would be the right option- and I heard they also take a very long time.

We need to go to the US urgently for family medical issues and my family would like him to come and visit them urgently due to their medical state. They have been waiting for 5 months as he has applied for a B2 visa twice, and got denied twice as they believe that his ties to Taiwan are not strong enough.

Do you have any advice or suggestions on what to do- or are we out of luck and need to keep toughing out on the b2 visa.