At my current employer, remote employees are expected to come in 4-6 times a year for 3-5 days at a time. Economy airfare, hotel, and a per diem for meals are all paid for by the employer. (I happen to be a local employee, but about half of my coworkers are remote.)
At my previous job, before COVID, there were some people who worked remotely and I am fairly confident their travel was paid for by the employer as well.
I would be surprised if your husband's potential employer did not pay for this. Once your husband has an offer and is in the negotiation stage, definitely confirm the company's policies.