Will And Testament

My father is looking to write a Will and wanted to give his entire property to just one son. We are two brothers. I am younger. My father is fade up with my elder brother as he has taken a large amount of loan from my father and not returning it back within the promised time. My father has some ancestral properties (land) as well some personally earned property(FD, mutual funds, share market funds) which he has earned whilst service, and its been 5 years he is retired now. Now my father is willing to write this Will to give everything to me(younger son). So, can he give all his properties (ancestral and personally earned) to just one son? Also, if he can not give his entire ancestral property to just one son, then is there any way where my father puts a condition on the Will by which the elder brother needs to pay back the loan amount only then he would be eligible to get his share on ancestral property. Waiting for your reply on this matter.