Make sure he has a big enough house. Syrians often pee in their houses, away from their nests, but if their houses are too small they end up sleeping and peeing in the same spot and it gets very messy. And then you have to choose between removing the wet nest (and usually hoarded food) and upsetting the hamster or leaving them with a wet nest, neither of which is a good option!
The plastic house I can see in your bin will be too small for a Syrian. You want something approximately 30cm long, with a roof that lifts off so you can spot clean it without destroying the nest.
I have
this house for one of my dwarfs. For a Syrian you probably need the bigger 33cm size.
Some people also have the
multichamber hides with different rooms, which serve much the same purpose. Basically they need a house where they can have separate corners or rooms for sleeping, peeing and hoarding.