1) will can be revoked only by testator
2) sons cannot amend father will
3) however the legal heirs can enter into deed of family settlement for division of father properties
4)once deed of family settlement /partition has been entered into it would be binding on the parties
5) on death of unmarried sister all her brothers would have equal share in her movable and immovable assets
6)it is immaterial whether they supported her or not . had the sister desired she could have executed will bequeathing her property to brother who looked after her . since she did not do so all her brothers have equal share in her jewels and other assets