Will and Inherited property

Sir/Madam, 1. Me and my last brother inherited my elder brother's property on his demise after a partition suit. Final decree was issued 5 years back. 2. I am not married and have no children and other brothers or sisters are not alive. 3. I have formed a trust on my family name. My friend' s son is taking care of me for the last 7 years. I underwent 3 surgeries in the last 3 years. 4. If I bequeath my property by registered will to the family trust and some portion to my friend’s son, can it be challenged by my brother or his son that as it is inherited property, I have no right to write such a will and they are the rightful owners on my demise and the will is null and void. 5. If yes, if I gift the inherited property to the trust and my friend’s son, and whether the gifted property can also be challenged by my brother or his son on my demise. 6. I three lawyers in Hyderabad and each one of them gave divergent opinion. I am confused and at loss to take any action by way of writing a will or gifting. Your advice and clarification will be highly appreciated with all the humiliation and respect at my command. With profound regards