My mother wont see her malicious son for what he is

My mother is so far in denial she wont see what is going on, which means idiot LayZ boy can continue to behave just how he likes without any fear of reprisal.

I just found out that he has been telling our mother that he often sees me in their bedroom (a total lie of course) when they are not home. Not only that, he also told me earlier that our mother told him that she has found some of her documents moved around in her drawers and that she told him she suspected I did it (apparently another lie).  And he swore to God that it was true (again lying and he was swearing to God, but still lying). This means that you cannot trust anything he says, because he is totally deceitful. How far do his lies go?

I asked our mother if she said that to him and she said she didn't. He then said, "Oh that's right, you didn't tell me that, I was just joking to her". Right, so swearing to God that he was telling the truth to me and now he tells me he was joking. How deceitful!

He's been telling our mother that he's seen me in their room to deflect from them thinking it's him who is actually going through their documentation and personal stuff, because our mother has noticed things out of order, like someone has been going through their things (she has a bit of OCD, so she knows when her papers/documents have been moved even a centimetre) and to deflect from her thinking it was him and because he knows she will believe it, he's apparently been telling her he has seen me in her room, so that no blame comes to him when he starts stealing things. God knows what he does when I am not home and he has complete freedom to do whatever he wants.

I told our mother that he "swore to God" and he swore on her life that she told him she suspected me of going through their drawers and that shows he's willing to lie to save his ass. She doesn't want to hear it and told me she thought it was our step-father who must have been going through the drawers. She wont listen to me, turns her back to me when I am asking to listen and then walks away because she is "upset". Like this is all about her, when its me that suffers. She doesn't know to know how sick in the head her son is, she doesn't want to hear that he is invading her privacy and her private documents because she wants to continue in her delusion that he is a "good son". Un-fucken-believable.

This all happened when they were in the family room and I asked her about the conversation she had with LayZ boy about suspecting me of going through their drawers and I told her again that I saw him with my own eyes earlier going through their drawers and he got so upset (I didn't realise it at the time why, but now I know that he was angry that the truth was coming out and he would get caught the deceitful fuckwit). He finally left after she told him to go, but that was not until after he started saying all this crap to me and lying more to try to save his ass.

It's irrelevant though, because our mother does nothing about him. She and my step-father have created a monster in their son. LayZ boy is a pathological liar. He will take start stealing from his parents (he may have already because they have some stuff that he could have sold in their garage and they wouldn't know unless they went through everything and itemised it all).