First time I have ever met a Nepali or even heard that there were any in the U.S. We had a nice conversation in the course of which I learned that Nepalis speak Nepali, which is very similar to Hindi and Punjabi (which are similar to each other). He can manage those languages since they are close to Nepali. He told me that the official and most widely used language of Pakistan is Urdu, which he can partly understand since it's similar to Punjabi, but he can't read it because he doesn't know the alphabet used for Urdu.

As it happens, I met my first Nepalese family at church on Sunday. As to the Nepalese man you spoke with, I am now quite convinced that he is half right - Urdu (a sort of lingua franca, like Swahili in Africa) is the official language of Pakistan. It is not, however, the most widely spoken, being the mother tongue of comparatively few people. Ismail Merchant is a native Urdu speaker, and many of his solo films have been in, and about Urdu. Urdu is written in the Arabic alphabet, IIRC.