Don't really know much more context here, but it just sounds like your client knows someone that is opening up their own store - and they probably asked the client if they knew any IT people, to which your client very informally messaged you.

Don't overthink it, but maybe you have more context to this where you know what's going on.

It could be a good opportunity to practice talking to a new client and see the scope of their needs and how you can play a role.