hey , gosh you have been through alot , and i dont have any answers . but there is a toilet behaviour lady ( dont know what they are called :P )
near me and i have heard her speak a few times .

maybe a pshycologist needs to be seen, if he knows he does it , there could be a reason why, which needs to surface , and when it does it will go away.

or a behiavorial therapist.... they could help....

as i said i dont know the answer , but for your sake , and the rest of the familys sake , counselling could work ... kwim

i am thinking about your dss on camp. i hope nothing nasty , like teasing come from it....

and shun me if you may , but the mum needs to pull her socks up by the sounds of things , take responsibilty for her son ... place the task back on her ... and if she doenst activley want to care for her son , then there may be other issuses the need to be adressed ..

you have exshausted all you can, hugs for you ...