Q: family sharing

No, the family organiser has to have a valid payment method on their account (e.g. credit card) as they are taking responsibility for the family members purchases : Family purchases and payments - Apple Support

When you set up Family Sharing, you'll be asked to confirm that you agree to pay for purchases initiated by the family members you invite and that you have a valid payment method on file. See which payment methods you can use with Family Sharing. If you need to, you can change the billing method on file in your account at any time in your iTunes & App Stores account settings.