Metin's place is just next to Gulhane Park, some 20 meters up the Soguk Cesme Street. It's located amazingly close to everything in Sultanahmet, thus giving you ability to get to most monuments in 2-10 minutes.
There are two small bedrooms (one with the toilet), and a guest room.
One morning we had an issue with the water pressure, thus we couldn't use water in the toilet / shower. That was fixed in a couple of hours, but it was a municipal issue, not Metin's.
Overall, it's a great place and I'd definitely recommend it to anyone who wants to get around Istanbul's UNESCO-protected old city :)