Can donor hair for FUE be from someone else (child or sibling)?

You cannot harvest donor hair from family members.  The only exception would be a genetically identical twin.

No, unfortunately the donor hair cannot be from another person, even a close relative. The tissue will be rejected in the same way that a transplanted organ is rejected. Work with a skilled hair transplant surgeon to determine all of your options regarding hair transplant and different donor site techniques. Best of luck!

The patients hair being transplanted must be from the patient themselves. If you are concerned about not having enough hair to donate into the desired area, a qualified and experienced hair transplant surgeon can take grafts from the chest, underarms, and even the groin area if there isn't enough donor hair on the head. If you are interested in FUE, find a highly experienced, qualified hair transplant surgeon who specializes in hair transplant surgery in the US and schedule a consultation to determine whether you are a good candidate .