Site for People with Prader Willi Syndrome

My sister has Prader Willi Syndrome. For those of you who don't know what that is it's a condition where you are always hungry and you have a slow metabolism. It also can cause some behavioral problems and cognitive difficulties.

My sister found out I build websites and she asked me if I would build a website where only people with Prader Willi can join. She wants it to be a social media site with games like Scrabble.

So I'm writing to see if anyone was interested and if anyone had any advice. I'm a CS student but haven't gotten to any major classes. I know vanilla PHP and have done a lot of WP development. I'm working on a React / React Native / Express app and I really like these technologies more than PHP.

If you have any advice for working on this, even if it's wait a year or two I would like to hear it.

The biggest problem is making sure that someone has Prader Willi Syndrome. We would have to moderate it (people would volunteer to do that). But my idea was to have a person take a photo of their doctor writing that they have Prader Willi on a prescription pad. If anyone has better ideas please let me know!

There is also a database that the PWS organization has. But they are probably weary about giving access and they are only the United States.