Sina and his family are very nice, kind, and friendly hosts.
When we arrived, early check-in was provided to us by Sina's sister who works in a nice cafe on the 1st floor of the building. She explained to us the main points of the city and staying.
The next day, we met Sina who told us where to go, where to buy food, how to travel, where to take drinks, where to find vegan (!) food. We were talking for like 2 hours, he fixed minor issues in the flat (like one bulb which didn't work). It was an extremely friendly and positive conversation.
The flat itself is a lovely place with a beautiful view. It has everything you need (and if something is finished, you can always ask Sina to give you salt, water, etc). It is located in a good area of Istanbul and has many shops near it.
Our stay was perfect, it's the best, most helpful, and friendly host we've ever met during our 10+ reservations via Airbnb.