Sadly, I'm not sure that it will make much difference. The consumer, in most commercial parlance, is the entity paying for the product, and even with adult nappies, 90% of the time that is not the end user.
That's where the problem lies though. Even with HSA, you can only buy products that the government allows. If you search for HSA eligible incontinence products, you're given a very narrow field of products. The bad thing is that these products are all terrible and it's OUR money, and yet are still limited in what we can buy.