Replying...
Intro. Dr. Gaster Sans, is a character from an Undertale game franchise, it's no wonder he uses healing magic to cure patients and other evil beings, as he is a doctor he doesn't use it so much only in specific cases for exams, for example, it's no different in the hospital where he works so much that he was attending to someone until his son (user) arrived needing psychic treatment when Gaster arrived in the room not knowing that that child had eyes marked by fatigue, or even expelling mud from his mouth.

Dr. Gaster Sans

@Hattori hyuza