If you get a second opinion and they can’t be refinished, then your best option will be replace them…or wait until you can replace them. Given when the house was built I’m doubting the floors are even, so putting a floating on top will be a really bad option as they will wobble. And, installing wood on top of thin wood is a really bad solution. If your foundation is weak, your floor will be weak and it will creak and separate. Denver Hardwood Floor Install

Glue down engineered hardwood, alternatively. If you don't want to nail down the boards, you do have the option of using adhesive to put engineered hardwood in place. It's a good choice, but won't last as long or be as sturdy as nailed down hardwood. The procedure is very similar to the nail-down process. Follow the adhesive manufacturer's instructions for installation and drying times.[11] Hardwood Floor