Am at wits end as is often case. Ds Asd aged 14 frequently tears up, damages or bins things. Partly odd type behaviour also seems to get some kind of pleasure from it. He does not do it in a meltdown, is non verbal and I have no way of preventing it. I have locks on everyone else's rooms but his room is obviously not locked. He has removed sheets, destroyed several pillows, posted his duvet out of the window and today ripped open the side of his mattress and pulled out quite a lot of the stuffing. What do I do? I am completely at a loss.
My Ds is quite similar but perhaps not as extreme as your son however he is only 5.
We have addressed this destructive behaviour by making sure all the windows upstairs are locked permantly. We have removed all memory foam mattresses ( he was eating them ), put pillows in several pillow cases and provided several pillows for him to unstuff which I then re stuff and sew up, he also has several soft toys he unstuffs. Luckily he doesn't eat the wadding so it's just a matter of mess to clear up.
Not really solving the problem but has made a difference on how much stuff he destroys or picks at. If he starts in the lounge or at the wall paper we try and re- direct him to his room.
I can't help with the posting stuff, we have tried to give him stuff he can post but he still posts things everywhere so I am never sure what I will find around the house and in the garden.
Plus we got him a mattress that has a zippable matress protector and then use a matress protector on top of that. It doesn't stop it but makes it harder for him and gives me time to try and get to it before he pull the insides out of his matress.