>>The ROSH writes that perhaps the Cheresh performs Hafarah through "Remizah," by motioning with his fingers. However, the Rosh concludes that there is no reason to assume that such an act would be effective, because a Cheresh who cannot speak is like a Shoteh, and a Shoteh cannot annul his wife's Neder (as the RAMBAM rules).

The Rosh, however, suggests another reason for why the Cheresh cannot do Hafarah through Remizah. He proposes that perhaps a Shoteh may do Hafarah, since Hafarah is not a Kinyan or a Mitzvah which needs Da'as. Hence, perhaps a Cheresh may do Hafarah with Kesivah or Remizah.<<

This seems to misrepresent the Rosh significantly. He merely says plainly that Hafarah through Remiza does not work, and also anyway a Cheresh is a Shotah. That is the full quote.

Moshie Cohen