Sale of gift deed property?

Hello, I have a doubt regarding the below case CASE : - Mr X has been transferred a property in the name of gift deed, where it was X's grandfather's land where property I. e flat is constructed and X's father transferred it to Mr X 1)Does he have full rights to sell that property? 2)Son or daughter of X who are minors at the time of sale can object the sale as they're now majors in the court of law?