1. Assuming that your father died intestate and as per your narration, your father and your uncle were enjoying the property on 50:50 ratio.
2. On the intestate death of your father, his share of the property would devolve equally to his wife and children.
3. If your uncle, has decided to give his share of the property in your favour, your uncle can gift the property to you and your mother and your sibling/s can execute a registered Release Deed in your favour relinquishing their right over the property in your favour.
4. A nominal stamp duty for the release deed has to be paid (between blood relatives, i.e. b/w you, your mother and sibling/s) and regular stamp duty for your uncle's share to be gifted to you by him.