First, bellseeker, welcome to GardenWeb.

How old is her dad? Some elderly people lose their sense of smell and then neglect their hygiene.

I would not invest in the type of products that you are researching. The issue is not about products, it is about finding the cause of the problem and addressing that.

I would find it highly insulting to get this type of "gift" for Father's/Mother's Day.

He may have a health problem, bad teeth, kidney failure, or some blood disorder causing him to "stink'. I once knew a woman with terminal cancer who smelled like sour milk. Ask him if he's had a physical recently, and ask his wife (your mom, making an assumption) if he is tending to his grooming and health. A "gift" of cologne or deodorant is not a good idea. Graywings is right about finding the root cause, not a "product" that will fix it. Goiod luck. This is a tough one.