For a while, Eisen continued to give the sick in this 'hospital' the best treatment he could, which was only at the level of getting his children through the flu. All the other times that he treated people were during accidents or emergencies where he had to work with rough external injuries or needed to stop or hold back someone's bleeding.
He didn't know much about treating diseases other than classic 'home remedies' that were passed down in every family, so what he could do was mostly limited. Some people were scared of Eisen, obviously, but considering that the old man was concentrating heavily on seeming calm and gentle toward others, his charisma stat and his titles worked against his appearance and current Demon title, meaning that he was able to convince people somehow he wasn't a bad person. Especially after he already began helping some of the other patients.
Send some love to my second novel, Demon's Virtue!
https://www.webnovel.com/book/15238973305579305/Demon's-Virtue