ANSWER:

Tell him that by paying rent, you are rewarded for it as it is for halal accommodation. When you buy a house in mortgage which is riba based, you are fighting Allah and His messenger and Allah Will wage war against you as it is a major sin islam.

My son in law feels sad giving rent like he is wasting money so someone advised him to buy a house on mortgage, even though he knows its haram, they gave him various logics. I want to convince him, can i explain that the rent you pay will count as charity towards your wife and children.