That scents can influence our mood is nothing new. They work very directly on our emotional center, and this applies to your cat(s) as well. However, cats do have different scent preferences than humans, and it is therefore common knowledge that cats are crazy about the smell of catnip, matatabi, and valerian.
Apart from the scent of catnip, which hardly any house tiger can resist, every cat has its own highly personal taste. What is a delightful scent to one is rather an unpleasant odor to another. Especially with sick or recovering cats, you must be careful not to expose them to a scent they find very unpleasant. Therefore, test your cat when he is healthy. The best way to do this is with scent pads.