1: You can sue him before the patent comes down, but it's only a civil dispute. You may not win the case without evidence. After the patent comes down, you sue him. This is a patent infringement case. He wants to pay you a large sum of compensation. What you have to do now is to get this patent before he applies for it.
2. You belong to a trade secret case. Specifically, we can refer to the laws of our country in this respect, or ask a professional lawyer to make a statement in person, and the result will be more accurate.