A good workforce of any establishment or factory is an asset, and there is no harm if HR indulges in the settlement of any sort of complaint or dispute, whether within or outside the premises. Moreover, I do not see any harm if HR even gets involved in personal issues of the workforce. I remember when I was in service, I had settled certain minor disputes within the families of workers or their friend circle. I understood their problems, whether related to school admissions of their wards or medical treatment of their parents, by advancing money either from my employer or from my own pocket. At the same time, taking appropriate disciplinary action against the guilty is equally important to maintain discipline and a peaceful working environment. In this particular case, if the employee has used abusive language through email, it is on record, and HR can review it, understand the circumstances and situations, and decide on further action. It is a goodwill gesture, and you can win over the hearts of the workforce. They will definitely listen to your directions always.
Regards,
P K Sharma