For the 20 years I've known him, my husband Chuck is sensitive to some airborne contaminants. His throat closes up and his voice turns odd -- it gets slightly hoarse and the pitch goes up. As soon as he gets away from the problem, his symptoms immediately go away. He never has systemic symptoms, meaning symptoms distant from the exposure site such as headache, swelling, hives, faintness, etc.
Some fragrance oils and colognes trigger this reaction. EOs seem to be pretty safe, at least the ones I've tested on him so far. Any smoke of any sort -- wood fire, cigarettes, cigars, burning leaves -- is also an issue. Whenever I get a new FO or try a new EO scent blend, I put a drop on a tissue and ask him to whiff it lightly. If his voice turns funny, the product is out the door, no matter how nice it smells. Even small % of a scent he's sensitive to will trigger his reaction. Given all this, it's weird that he loves his pine tar soap. As smoky and pungent as PT smells, you'da think it would bother him, but it doesn't.
I'm not remotely saying your friend is like my husband, but if he happens to have something similar to Chuck's sensitivity, he's probably not in any great danger compared with someone who does have a systemic allergic reaction. He needs to test his fragrances cautiously. It may be that some fragrances are fine while others are not, but there's no way to know that without testing each one. Maybe put a drop of new cologne on a tissue, sniff that for awhile, and see if his symptoms appear.
After this many years, Chuck and I have gotten a clue about some things, but we've never figured out specifically what chemicals will trigger Chuck's reaction and what will not, so it's kind of a guessing game when encountering new scents or other airborne things.