intestate succession property transfer

My father is 82 yrs and a ex-railwaymen, he bought a plot in his first wife's name,she died 40 years ago,in land revenue record,land is still in her name.She is survived by her 2 kids.I am his 2 nd wife only son.can my father gift or will his 1/3 share as he has not transferred/ mutated plot in his name yet.Is 1/3 share that he owns by intestate succession of late wife not his self acquired property which he had funded for wife and upon her death,1/3 rd share automatically get transferred. in his name.kindly tell if he can will his share to me and if it will be valid.