I am disappointed in my daughter-in-law

My son is doing well. He and his wife have stable incomes, they get along well, and have a son together.

My daughter is not doing so well. She and her husband rent a home near ours, but they are struggling. Last year, her husband informed us that he was VND200 million ($8,533) in debt because his business was not doing well.

He also owes my son VND30 million and owes my younger brother VND40 million. He sold his family's land in the countryside to pay the debt, but could only pay VND100 million because market prices are low. He asked me to borrow money from my relatives on his behalf.

I asked my daughter what kind of business her husband was doing that led to this situation. It turns out that he borrowed money online to gamble.

I feel sorry for my daughter since she married a terrible husband. She does not want to divorce him because she wants her kids to have both a mom and dad.

My daughter is now on maternity leave. Her husband only gives her VND2 million a month to pay for the kid’s milk and diapers. Meanwhile, they still need to pay VND2 million for rent and they have two small kids. I've told my daughter to come to live with my family to reduce her living expenses.

My husband works as a security guard, earning VND7 million a month. My son pays us VND5 million for housing expenses.

The main issue is that daughter-in-law is very annoyed with my son-in-law. Once I overheard her complain that he is being unreasonable for not sharing living expenses and housework.

Knowing that living together can lead to many conflicts, I want to build a small house for my daughter and her husband so they don’t need to rent a house anymore. I and my husband only have VND200 million in savings, so I asked my son to lend his younger sister VND300 million to build the house. I know my son has some savings, so I think it’s better that he lends to his sister when she needs it.

My daughter-in-law is not happy with that at all. She said she did not want to lend money to someone who can’t repay it. But I argued that it wasn't her place to say so since she sends all the money she earns to her family (her father is seriously ill).

She cried, said nothing, and went back to her room. The next day, my son and his wife said they wanted to move out and live separately. They gave us VND70 million to help build a house for his sister’s family. He said he would give her that money for good, not lend it.

Now I am very confused. I don’t want a quarrel in the house. I am very disappointed about my

What should I do to maintain harmony in both my son’s and my daughter’s families?