From: Rabbi Moshe Sofer
To: Rabbi Aharon Hersh
The student asks about the limits of the principle that 'a person is pleased to have a mitzvah performed with his money,' particularly how it justifies giving tzedakah from an insane person's assets when the loss is significant and involuntary. The Chasam Sofer develops a comprehensive framework distinguishing cases of no real loss from actual expenditure, and argues the Kesef Mishneh specifically invokes tzedakah because its life-protecting quality uniquely justifies the presumption even for a shoteh.
Source: Shu"t Chasam Sofer OC §2