His father's income is 500 USD per month and they use 400 USD for monthly needs. Furthermore, he was just a student and the whole family depended on his father's sole source of income. Do you think his family can have a fund of 10 thousand dollars?
You misunderstood it. His father earns 500 USD per month and sends 400 USD to them to support their family. Did you notice his father spending $100 per month only to live in a country like Malaysia? That does not really mean they spend all their 400 each month. The cost of living in the village side of Bangladesh increased in the last two or three years. But before that time, even $50-80 was enough for a two or three-member family to cover up the expenses. Everything was way cheaper than it is today. If you talk about today's expense, it won't exceed the $150 limit for a member's family if he lives in the village side because most of the people live in their own houses and have firm rice and necessary vegetables. I know many family who's monthly earning was around $500 a month, and they have $30K cash in their bank. If he lives in the town side (Which I guess is not), the expenses are totally different.
150 USD/month for a family of 3 is a quite modest number for me, it's really a very low standard of living compared to the standard of living in my country. My family consists of 4 people, every month I have to spend about 400$-500$ and we are a poor family, belonging to the low-income class in my hometown. I am actually quite surprised with the level of spending in Bangladesh, it is so different from my country while my country is not richer than Bangladesh.