Is it appropriate for parents to ask their sister to buy clothes for their younger brothers and sisters?

Suitable. It is appropriate to think that it is the most convenient and appropriate for my sister to buy clothes for her younger brother and sister, and at the same time, my sister has enough financial resources and time. Need to consider the relationship between brother and sister. If my sister has a harmonious relationship with her younger brother and sister, and my sister buys clothes out of love and concern, then this is appropriate.