Mina, this is the translation you asked for: إستشفع بها إلى الله لیُعافیَهُ: He was pleading to Allah by it to cure him.

ليعافيه =معلوم because the subject الله and the sentence mentions الله مبني للمجهول when delete the subject ex: هو كتب رسالة He writes a letter الرسالة كُتِبَت A letter is written

I think it is مبني للمعلوم this Dammah of the يــ is an original one. not the one of مبنی للمجهول