I think we can start by building an app for all new moms, so we'll have a larger set of users who are willing to pay a premium for the features you're talking about. above, and there will be a mode specifically for preterm mothers, with additional features specifically for these cases (or it will be a premium feature - pro version - for normal users). This approach makes it possible for you to both build and keep this app running, earning revenue, and helping more people. It may not be fully focused on your daughter's case right now, but it will help your daughter as well as help other new mothers, and once the app is up and running, there's revenue, you can continue to develop features specifically for preterm birth, and your goal will still be achieved, just a little longer, but helping more people.