IRREVOCABLE POWER OF ATTORNEY

All types of power of attorney becomes inoperative after the death of its principal even if it made with full consideration. So instead of power of attorney or with the help of power of attorney in the lifetime of author you can register a sale deed. It is the best alternative. 

Legally speaking Power of attorney is not supported with consideration. If consideration is shown, stamp duty has to be paid accordingly.

For conveneince and to avoid payment of stamp duty, parties do not show passing of consideration. If it becomes inoperative due to the death of principal, problem arises. In such cases, fresh power can be got from the legal heirs of deceased principal.

To avoid such difficulty, as shilpa said, execute the sale deed as early as possible .

if the power of attorney executed is irrevocable, even after the death of the principal the Power of attorney cannot be determined and it can be acted upon, as there is an interest created on the agent as contemplated under section 202 of contract act R/w.section 201 of contract act.

see the attached supreme court judgement