QLD Brother in law disclaim inheritance

[leee4855]

I am the executor of my mother-in-law's will. She passed away 2 years ago and left my wife and my brother-in-law in equal shares of her estate which consists of a house and portfolio of shares. My wife and her brother have decided that all the shares be transferred to my wife’s name that is my brother-in-law is disclaiming the shares but not the property. Is a letter of transfer sufficient or a Deed of Family Arrangement needed. I am also the POA for my brother-in-law. Would there be a conflict of interest to sign on his behalf to facilitate the transfer?