1. On death of your mother the said proeprty devolves upon her legal heirs which include 3 of you and your father.
2. So your father has only undivided 1/4th share in the proeprty.
3. So your father can nit sell more than his 1/4th undivided share.
4.However to restrain him from doing any mischief you can file a suit for partition seeking your 1/4th share in the proeprty and injunction so he may not be allowed to sell any share till the partition suit is disposed of.