1. Do note that n death of your mother her property devolved upon you, your 2 sisters and your father in undivided 1/4th sahre.
2. So your sisters are already 1/4th share holder and your father can not transfer their share unless your sisters did gift deed or relinquishment deed.
3. So you have to act accordingly..
4. It is not clear from your query what exactly do you want to know or what was the mistake?