1. If your sister is entitled for an undivided portion of land along with her cousin, she has two options to transfer the same to same to him without approaching court for partition, I.e., by executing a registered gift deed or by an amicable registered partition and executing a registered sale deed insofar as her share is concerned, in his favor.
2. They both can mutually agree and adopt the procedure without approaching court and obtain the amount as per the terms mentioned in a written agreement.
3. The POA deed for court purpose need not be registered, but for subsequent representation before the registrar office, the deed should be by a registered deed only.
4. It depends on the situation prevailing at your end.