Is it permissible to give charity money to poor families whose members refuse to work, and does that cause their laziness, and is it a sin to withhold charity from them?

Your work in sponsoring poor families is great. There are two types of sadaqat (charitable giving): obligatory (zakat) and supererogatory. Zakat is only given to those mentioned in Surah At-Tawbah/60, and it is not permissible to give it to someone who is able to earn a living. As for supererogatory sadaqat, it is permissible to give it to both the rich and the poor, though it is better to give it to the needy. Therefore, if the sponsorship money is zakat, it is only permissible to give it to the poor who are unable to earn a living. If it is a supererogatory sadaqah, it is permissible to give it, and it is better to spend it on the needy. Supererogatory sadaqah must be spent only on the poor if the donor stipulates that. It is advisable to counsel those who are able to earn a living to work and refrain from begging from people.