New carpet causing allergic reactions

Hi I am a realtor. I helped my parents buy a new home in September 2020. We immediately got their walkout basement carpet removed, then had cleaners come in and clean the floor, then had new carpet installed. It is a medium pile carpet. I can try to find out the material. I wouldn't say it is a high-end carpet. My mom had allergic reactions right away, which we chalked up to being off gassing. But it is almost a year and a half now, and she and several of the grandkids all get red eyes when they are in the basement. Any insights or recommendations are very much appreciated. Both the installer and the manufacturer are dismissing the situation.

Thanks for the thoughts.
Fans not a factor here.
Area rugs not a desirable solution... would have to remove the whole carpet and replace with laminate or tile and then put down rugs. Expensive, and would still leave a hard loud (cold if not heated) basement floor.