This is really a personal decision. Hosts should do what causes them the least anguish. Judging by the hesitation, my guess is that this host should take the side of being more cautious.
Some people are really chill about Covid at this point, and others are the opposite - extremely upset that mandates are being lifted.
Most of us probably lie somewhere in-between. I don’t think even an epidemiologist can tell at this point the odds of spreading the virus in a given community, and how serious it would be for each individual.
Frankly, I’m rather surprised the guest opened up about their vaccination status. I don’t think most hosts ask for vaccination records. I’ve probably hosted a few unvaccinated guests during the past 2 years, as I don’t ask for records. The guest here has shown a certain sense of responsibility to have shared this. That alone would be meaningful to me.
The only advice I would give past that is to at least follow the mandates and guidelines of the specific governments, national and local. It will possibly avoid conflicts later to be in-step with the rest of the community. However, if hosts are comfortable with more restrictive guidelines, they should go with those.