Should I mention in my letter of recommendation that my student has bad handwritting?

A student I taught is really a good student but writes like he is writing with his wrong hand.

The college where I teach requires every one to administer a subjective final exam for 60% of the grade. Its a 3 hour exam and people usually fillout a 30 page booklet. I know many lecturers gave him bad grades because they were too impatient to read his answers they gave him B+ or a B when he deserves at-least a A. I know this cause I taught him Data structures using C and he performed very well while he got a mere B grade in a C language course.

Should I mention this in my LOR or will mentioning this have some bad consequence for him.

I can easily grade 3 students in the time I grade his one paper. So I can imagine how some universities could see him as a liability.