[Ali Imran]

What if he can't pay? What happens to him and his family?

Aiyoh.. how many times must answer this.

If an able-bodied man can't afford to pay, then no need to pay.

Let me tell you of an interesting story. When the Muslims in Spain were about to be defeated by the Christians, the Jews who were under the Muslim protection got their jizya refunded to them because the Muslims were no longer able to protect them.