Magar's picture has gone viral on Nepal's social sites, including Facebook and news portals, reported Xinhua.
His photo shows a glow on his face since his dream of being reunited with his family has been realised, all thanks to Modi.
Magar, from a rural village in Nepal, has finally got the opportunity to meet the rest of his family members after being separated for 15 years.
The 26-year-old boy had established contact with Modi in Ahmedabad more than a decade ago and had been taken care by Modi since then.
Modi's state visit to Nepal from Aug 3 to 4 is the first visit by an Indian prime minister in 17 years.
Magar arrived with Modi in Kathmandu in the Indian leader's special jet.
Magar's family members, including his mother, brother, sister, sister-in-law and two cousins, were brought to Kathmandu a few days ago by the Indian embassy in Kathmandu.
Xinhua said that the family reunion has been received huge applause from the Nepali community "because it shows the human side of India's new prime minister".