1) i presume it was your grand father self acquired property . on his demise once deed of partition has been made , duly stamped and registered your father is absolute owner of his share of the said property . he can bequeath land as he pleases .
2) only if your father dies without a will would you have 1/3rd share in property
3) as far as mother property is concerned your mother would be absolute owner of said property standing in her name . as on date you have no rights on said property
4) only if your mother dies intestate ie without a will would you have any share in said property