Being given operational work after joining in HR position - should he quit?

One of my friend worked for HR Department and gained 10 years of experience in HR. Recently he resigned his present organization and joined new organization (completed two months of service) the problem is that he interviewed for HR position, but he got the offer letter mentioning assistant manger without any department name but my friend joined blindly not confirming his roles and responsibilities now he was assigned operational work which is not related to his profile, and he is also not interested and many times he asked his reporting manager to change his role as per his profile, but he is not listening and talking sarcastically.
Please suggest shall I ask him to continue for few months or leave the organization and search for the job to his profile as he is getting calls for the HR positions.

Dear Saibaba,
Your friend, who has 10 years of service in HR was interviewed for HR position but was issued Offer Letter as "Asst Manager". Now he has been assigned duties other than HR and he is confused on what to do now.
A query like this, if comes from a person with 10 years of experience, itself is questionable. Moreover, your friend was in HR. How he accepted offer letter that did not mention a proper designation, is a point to ponder. Going further, rather he coming on this forum and raising a direct query, he has assigned this job to you! This is one more mismatch!
Anyway, he may choose new job in HR if he is getting calls for working in HR Department.
Thanks,
Dinesh Divekar