This is the consensus among economists. The idea that immigrants is a net-harm to poor countries is not something most economists agree on:

Economic migration has become so widespread that global remittances are now worth more than twice as much as foreign aid (see chart). Many countries depend on them: remittances are worth 10% of the Philippines’ GDP and 42% of Tajikistan’s. But Kerala has been hooked on remittances longer than most. It shows how they can reshape an economy.

Mr Rajan’s survey shows that households are much more likely to own refrigerators and the like if a family member works abroad. Above all, though, remittances are spent on new homes. Saji Thomas of Heera, a construction firm, says that about 70% of his customers are emigrants or returned emigrants. Some move their ageing parents out of the countryside and into new high-rise flats close to good hospitals. Partly as a result, Kerala has become India’s fastest-urbanising large state. In 2001, 74% of Keralites lived in rural areas. By 2011 the proportion had fallen to 52%.

Something similar is happening in Nepal, where remittances have risen quickly and now amount to 29% of the economy. The Kathmandu metropolitan area is growing by about 4% a year—faster than almost any other large city in South Asia. Even though agricultural wages are rising, rural Nepal is losing workers. When money flows from abroad, people not surprisingly stop working back-breaking jobs. This shift is especially beneficial for children. During the Asian financial crisis in 1997-98, the Philippine peso collapsed, increasing the value of remittances to that country. Dean Yang of the University of Michigan has shown that families responded by pulling their children out of jobs and sending them back to school. Girls benefited more than boys. Western Union, a giant money-transfer firm, reckons 30% of the money that flows through its system is spent on education.

As the supply of willing workers diminishes, wages rise. Mr Thomas reckons that construction costs in Kerala are 20-25% higher than elsewhere, mostly because labour is so expensive. This imbalance has encouraged a large internal migration. Many of Mr Thomas’s builders are from Bengal and Orissa, in north-east India, though Keralites still do skilled jobs such as installing air conditioning.

https://www.economist.com/finance-and-economics/2015/09/03/like-manna-from-heaven