The transfer of ownership of property depends upon the will and consent of the property holder, the person can transfer the ownership to anyone of his/her choice.
A grandchild does not have any birth right on the self- acquired property of his grandfather if it had been allotted to his father in a family partition in his capacity as legal heir and not as a coparcener under the Hindu Succession Act 1956. The grandfather can transfer the property to who whoever he desires.
If the Grand Father dies without leaving any Will, then only his immediate legal heirs i.e. his wife, son(s) and daughter(s) will have right to inherit the property left behind by the Grand Father.
As the properties inherited by the Wife, Son(S) and Daughter(s) of the deceased would be treated as Personal property of those who inherit the property, no one else has any right to claim any share in the same property.
In case any son or daughter of the grandfather died before his death, then the legal heir of the predeceased son or daughter will get the share which the predeceased son or daughter would have got.
The grandchild of the grandfather shall be entitled to get share of his/her predeceased father only, if the father is alive then she is not entitled to any share.