The problem here is there are limited officers working in Nepal. When I had my visa interview my officer was taking visa interviews for H1b, student visa, spouse visa, and B1/b2 visa. As I heard the whole problem of visa backlogs started in India meanwhile a couple of Indian origins congressmen like Raja Krishnamoorthi are only raising the concern of India while sending these bureaucrats officers working from Nepal to India to provide their consular services in India. We barely have visa officers left to conduct interviews in Nepal.

What you can do?
Ask your congressperson from your district to provide flexibility for visa interviews here in Nepal. Or else nothing can be done than to wait for the next few years to meet your parents.