My boyfriend started using minoxidil, but we don't live together. Should I be concerned for my cats?

My boyfriend recently started using topical minoxidil on his scalp and face. We do not live together, but I am worried that when I sleep over, I risk exposing my cats to minoxidil via his sheets, pillows, etc. since I will be in direct contact with his skin/face. If it transfers to my clothes, for example, will it still be toxic to my cats, say a few days later? Will I have to wash all exposed clothes/my hair before interacting with my cats?

Thanks for any advice - just super worried because I know it can be lethal to cats and want to take the best precautions to ensure they don't get sick :/