Co-parenting and suitcase kids

Hi all,I have an 11y.o stepson who we have on school holidays and 3yo son who lives with us full time. This is a multi-part question, let me know how you would handle each part.1 - My stepson brings a suitcase with him when he stays. Which has to date, spreads all over the floor mixing clean clothes, dirty clothes and other rubbish in one large "Floordrobe". How best to organize / unpack this when he arrives? I feel at 11, he should be taking better responsibility of his belongings...2 - He brings a suitcase because we tell him his belongings are his and he can do with them as he likes (typically take everything back to his mum's house were he spends most of his time). When custody was 50:50 he'd still manage to leave his room empty of all toys, clothes etc. Including even things like undies/socks (which I could never understand because you'd think items like that trade 1 for 1 when they go in the wash..) He only ever comes back with clothes and then complains he had nothing to do (expecting me to entertain him) even if we try organize it with him / his mum the week before he comes. Last time he even arrived without shoes so I would have to buy them for him. We've bought him MANY (some quite expensive) gifts which never return from his mother's house (laptop, ipad, iPod, psp, scooter, wii etc) and are never given a real answer "I forgot / I can't find it"3 - I believe he's stealing my 3 y.os toys and taking the back to his mother's. Super hero action figures, ninja nesting dolls, remote control car. He tells me his half brother is spoilt and has everything he can imagine. I believe this is how he justifies stealing them when his room looks so empty in comparison. I won't go through his case on the way out for "evidence" as it shows complete distrust and even if I could prove it, that's not a point of victory... via /r/Parenting http://ift.tt/2gHVdSB