@deeebeee That's not an easy place you are in. The more you show concern and want to talk about it, the more he pushes back. Is that right? If he's waking up with an almost severed tongue and soiled pants, he knows something is going on. You are probably right, it does sound like denial. Some people deal with issues my ignoring a problem. He could also be going through the stages of grief. The first stage is denial.

Below I have linked a wonderful resource. There is a lot of emphasis on death and dying but we can go through the stages of grief about anything.
https://grief.com/the-five-stages-of-grief/
•denial.
•anger.
•bargaining.
•depression.
•acceptance.

At this point he's probably getting more upset and pulling away more and more. Did I get that right? I hear that you love your son and you are desperate for him to get the help he needs. I can't imagine. This must be so heartbreaking. Unfortunately, you can't control what your son does or chooses to address but you can change how you react. I do not think you are reacting poorly. It just sounds like it's not working and there needs to be a different approach. You may want to think about few sessions with a therapist. This might serve two purposes. One, this has to be hard on you emotionally and psychologically and you can get that out. Two, the therapist could help you respond differently. Again, how you are responding is not incorrect. It's just not working. A therapist will help you reverse your approach. Instead of showing concern, you can act like it's no big deal. Hard I know. This is why a therapist would be best to help in this situation. If you act like it's no big deal, then he is no longer putting his energy into fighting you. He has to sit with the issue. I bet he's really scared.

I know I threw a lot at you and I hope it is helpful and not overwhelming.