I don't think the Major Brigadiar was a fool, rather Christine fair was foolish in her claims. He introduced himself as the Brigadier to establish his authority when correcting her silly claim. which really angered Fair who took it personally and started bragging dramatically about her Phd.
As per WIKI, balakot city in KPK has a considerable punjabi speaking population. Also, many hindko speakers know punjabi as well. That's why that Sikh Brigadier knew what he was talking about as he spent time observing the area during his military service.
The majority of the population are speakers of Hindko,[41] an Indo-Aryan language closely related to Punjabi, and also spoken in the rest of Mansehra District. There are also speakers of Gujari.[citation needed] The main city area of Balakot is inhibited by Gujjar, Awan, Swati, Syed, Turk, Mughal and Hanki [Yousafzai, Madakhel]tribes.