I'd get Yasin to learn about keeping his area clean and tidy, that if he doesn't then mummy will come in and clean and move things around. Even if you get funky plastic boxes for him to keep things in (so they can double as tables or play areas).

my brother & SIL had the kids playroom, which was separate from their rooms (it was an extension off the side of the house with sliding doors from each kids room), which was the kids responsibility to keep tidy and they knew that if they didn't pick up the toys then it didn't get cleaned on cleaning day and was then out of bounds until they cleaned it (we used to lock the doors and they had to ask to go and clean it so they could play - it took about 4 or 5 times of not being able to play before they got the idea of putting things away).

DH's boys are grots, their mother never made them clean up after themselves and now 2 of them are teenagers I pity the poor female they end up with, DH used to try to get them to clean but what they did at "Dads house" was undone when they got home.