Actually he is ready to write whatever I tell him to write. So basically he can write me the best letter possible but I am not sure what should he write other than praising me and strongly recommending me.Why dont you ask him can you write the letter yourself and he just sign off on it since he dont know what to write. Had a professor that does this at my university.
My dentist asked the same question. He said he needed my help writing one and he didn't know what to write. So I gave him my resume and let him know what I've done/accomplishments and stuff but he still hasn't written one yet....but he asked me what should he write. What should I tell him to write? He asked for points on which he could write on.