People forget projects like this are done for fun. They put a lot of polish and organize it well enough that it looks professional, but just like this, it can be a single dev working on it on their free time. its super easy to create a project, get busy, and just fall off. They're allowed to do that, plus while there's always more stuff to do, even the existence of this app is already impressive, so I thank them for the work, and until I decide to start coding during my free time instead of playing video games or watching TV, I try not to be disappointed when a project slows or even dies.

I hope the original dev is doing good, I thank them for their work, and congratulations on the twins, hope everything is going well for them, and hope they only come back when they feel ready, not when they feel forced to