https://wiki.radioreference.com/index.php/P25_CAI describes the issue if the hospital has P.25 radios. If you are referring to what Motorola uses for P.25, matching C4FM would not be sufficient; matching bandwidth to narrow is not sufficient. Some radios that Motorola made support Gaussian Minimum Shift Keying. A study of Vocoders and IMBE would answer the question as to why his Yaesu radio may not be able to 'pick up' audio from the hospital Motorola radio during a scan. Trunking may also be involved.