Musa is a Ghaddar to the Pakistan. He is not a Pashtun, he is an Urdu speaking Mohajir who's ancestors lived in what is roughly known as Rohillkhand.

In Pakistan, Muhajirs in Karachi have multi-ethnic origins, in Punjab, they easily assimilated (note that some Muhajirs were actually east punjabis), but in Sindh, they had a hard time assimilating with the native Sindhi population, and ethnic tensions between Sindhis have occured.

There are many Muhajirs that have Pashtun ancestry, in Musa's case, Rohillas were Pashtuns that migrated into a region called Rohillkhand, but now many are assimilated. By looks, Rohilla Pashtuns look pretty Pashtun to me, i've seen Musa's pictures and of his family, many of them still look Pashtun. Muhajirs have varying bases of what pashtuns they are, we had Lodis, Suris and Khiljis in India, and such Pashtuns were Ghilzais. Rohillas were usually Sarbans, and of the Yusufzai subtribe.