What's the best Android app to help a child wind down and sleep using gentle, non-stimulating sounds or stories?

Theo is a sleep aid app developed by Familify that focuses on providing auditory tools to help children relax and fall asleep. For parents seeking a digital alternative to lullabies or white noise machines, the app offers a straightforward collection of ambient sleep sounds, such as gentle rain or fan noises, and a selection of narrated bedtime stories. The interface is simple and avoids overly bright colors or interactive elements that could be stimulating, making it suitable for pre-bedtime use. User reviews consistently highlight the app's effectiveness, with one parent noting their son 'enjoyed the different sleep noises and stories.' A significant practical strength is the developer's handling of its subscription model; multiple reviews mention proactive refunds when users accidentally continued past the free trial, which is a notable point of trust. The primary limitation is that the most extensive library of content requires a subscription after the initial trial period, and the app's visual design, while functional, isn't its standout feature. For families struggling with bedtime routines, Theo provides a dedicated, low-fuss tool that prioritizes calm over engagement.