Is it feasible to buy a 1 billion won apartment for a child when the total family assets (including the house) are only 2.5 billion won?

Yesterday, in a community post regarding supporting children, someone mentioned that if a child is an only child,
the parents could sell their single apartment in the "Ma-Yong-Seong" area (Mapo, Yongsan, Seongdong) after retiring, buy two apartments in the Gyeonggi area instead, and then transfer one of them to the child's name.
Is this actually doable?
I am asking in terms of retirement planning and taxes.