Consideration amount payment for joint owners

Both of them may be paid consideration through same account, which should be agreeable to them.

However, there is no legal issue involved in your post, which may be considered and obliged.

you are bound to act as per the POA. 

The posting suggests no legal elements. Depositing of the consideration is a matter of mere convenience.

it is ok even if one of the owner accept the amount but the thing is that the joint owner must agree for this and for that you may put averment in the agreement

 

Better open a Bank account in the name of your Sister-in-law also and credit the amount to both the joint owners to avoid income tax problems with regard to capital gains etc.

Further, the sale proceeds need to be credited to the NRO account only and not to NRE account domestic account (they are not supposed to maintain domestic SB account) if any. Once the transaction is completed the NRI joint owners can transfer the money to Australia subject to a maximum of USD 1 million Dollars each equivalent INR duly submitting Form 15CA& 15CB to te remitting bank where they gave the NRO account..

With getting an written consent from wife,then the POA holder cannot deposit the entire consideration amount in the husband bank account.The wife can question the same with POA holder.