He has been detained by the public security organs on suspicion of "fraud". How can it be a big problem? Unless there is insufficient evidence (the medical care case uncovered in Shanghai this time is a major case, and the evidence is basically determined through long-term evidence collection), or your daughter's involvement is not deep and the amount is not large, it is possible to be exempted from prosecution.
Otherwise, you will be prosecuted and sentenced.
You can go to the public security organ and ask the police handling the case. If you can't be exempted from prosecution, it is recommended to hire a lawyer as soon as possible (if the case is simple and clear, the evidence is conclusive, or the crime is minor, you can not hire a lawyer).