Since it is an ancestral property, every member is equally liable for each share. You sisters can only give that share of the property which comes to them as per inheritance. In simple language, sisters cannot say that they are giving full property to younger brother, it is just their (sisters') part of share they are giving. and yes, elder brother can file case claiming his share out of that property. For any further assistance, feel free to contact me on my e-mail "firstname.lastname@example.org"
Shubham Pabbi & Associates