answer is in the question itself: there is nothing in nepal, so it is expensive.

bangara phuskini gari dinu parthyo ni tehi thau ko tham.. ani cops aaye pachi , self defense bhannu parthyo

Stop wasting ur time

Tell that dhoti that we don't have that much rapists, child molesters n criminals thats why our Kathmandu is much expensive than his cities

Bro, that's real simple. It's got to be Buddha and Mt Everest.

Don't demonize him too much. There are some uneducated/uninformed individuals from India like from anywhere else.

Here are some facts that you can consider educating him with. Some points could be little feisty, but use as needed.

- I don't see India started with whole lot either. Regardless of how much money super-rich Indians have, real India is still running on remittance by hardworking Indians abroad. $71B dollars in 2013.
- Since British took Indians to foreign countries to dig canals or produce sugarcanes, they started going abroad before Nepalese did. Both are in the exact same path, just different timeline.
- Since boarders are open, people are crossing both sides. There are several dirty jobs only Indians do in Nepal (khali sisi, cleaning septic tanks, collecting trash by river banks) (I know others are doing it too nowadays).
- There was a report in Kantipur a couple months ago, it said a huge percentage of total remittance Nepalese receive from abroad is further remitted to India by Indians working in Nepal. Google it. It was huge like 25% of total or may be even around 50%. I don't remember the number.

- Income gap is so huge in India, doesn't matter how Ambani's jack up the average per capita, but majority are in much more deep shit than majority Nepalese.