I understand the guy’s preference, bank wires cost real money but EU SEPA transfers are quite cheap. I’m quite sure that’s what he wants to be able to do. And ideally that’s what you want as well.
It sounds like what you want is a simple EU bank account. It shouldn’t matter what country it’s in since you only really care about doing the transfer out back to the US. I’d presume you would want it anyway since your husband is having to deal at least somewhat in EUR.
There are several ways to do this.
If your husband is actually physically in Denmark with a visa, he can probably find a bank in Denmark that will open an account for him.
It is supposedly not that hard to open a bank account in the Netherlands, it just requires visiting and jumping a few hoops. I’d have to find the right reference for doing so. People have done it. Obviously that’s problematic at this moment though since they do insist on the physical visit to the bank and to the office where you get a ID number.
N26 bank may do it for you, esp if you can provide a Denmark address. I haven’t looked into it.
dukascopy bank in switzerland will open accounts for US citizens. Fees though. But part of SEPA.
Transferwise is a good solution as suggested. I’d suggest it’s probably the simplest solution for your need, versus cryptocurrencies or the like, since all you want to do is move money from A to B and have a EU-based IBAN to give to your client and maybe you want a credit card.