Respectfully, this is a medical issue, not a legal issue. I hope you get the help you need..............

In order to successfully sue, you need to show that the product was somehow defective. An allergic reaction is not enough.

On the off chance that this is a serious inquiry, the answer is no, you cannot sue them for not honoring the coupon.

This is a Q&A forum. You have not asked a question.........................................................

You can hire a private investigator, but you have no grounds for a lawsuit under these facts..........

In all likelihood your sales contract will state which state's law applies. In most states Lemon Laws only apply to new car sales.

This is a Q&A forum. You have not asked a question. But the answer is that he needs to retain the best lawyer he can find. Obviously, her version...

If you have attorney's fee you have an attorney, and you can ask them. IMO, you are not entitled to a free rental.

These are questions for his lawyer, who knows more about the case than any of us (or you.)...................

I don't know what you are asking. Your post is very hard to understand. Maybe you used voice to text. Perhaps have someone help you repost it.