it is permissible
for a legal guardian to encourage those in his charge to do what is possibly or certainly good for them, and it is not permissible for him to encourage them to do anything that might definitely or possibly cause them harm.
a guardian is obligated to pay Zakah on the money of the minors under his charge if their money reaches the Nisab (the minimum amount on which Zakah is due) and it has been owned for one year. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.