your friends parents have logic issue here.. 3 years is not 13 or 30 years difference... 3 years is nothing at all.. The girl was still a baby when your friend was born..

Tell your friend that he is the one who will be living with his wife forever and not his parents...  they had their good relationship with each other and now why they are being obstacle in their son's married life with the person he loves..

Nepali parents try to be selfish;.. grow up parents... happiness of your kid is happiness of you both old ppl...