1. Can she still ask for partition as per 2005 act ?
She can very well claim for partition and separate possession of her share n the property. She first has to file a suit to cancel the registered gift deed on the grounds of fraud and fabricated documents agaisnt the fraudster grandson.
2. Can she ask for declaring NULL & Void the 2 deeds based on HUF document?
She has to file a suit for declaring the said deeds as null and void for the reasons that they have been obtained under force, coercion and by playing fraud on her.
3. Can my husband recover his share?
He too shall have to file a suit to declare the relinquishment deed as null and void for the reasons that this was obtained under his influence fraudulently.
Simultaneously he can claim partition and separate possession of his share in it.
4. Do I also get any share upon partition.
Not during the lifetime of your husband.