I would go with the Chase Sapphire Preferred (either for you or your husband) so that you can transfer these points to his Mileage Plus Account.
I would also open a Chase Business Card (either for you or your husband) that can also be transferred to his Mileage Plus Account.
And if you need more points you can open the Chase Explorer Card (1 mile for every $ spent) or United Club Card (1.5 miles for every $ spent and United Club Access - which he already gets as 1K when flying intl).