As I mentioned above, your husband can show his SPG Gold card or app at check-in & ask them to extend the courtesy of lounge access. If they do; great. If they don't, be gracious & accept it - & for goodness' sake, don't argue w/ them & do the but my hubby is a gold thing.

They're not required to offer lounge access to a non-elite member, and it's not the property's problem that your husband hasn't linked his accounts (not that that would technically matter in this case since the ressie is still in your name).

If they do offer lounge access, they're doing so as a courtesy & not because they're required to do so.

Cheers.