Can a grandfather leave property to grandchildren

Yes he can execute a conditional will because properties are self acquired properties of the grand father.

Instead of going indirect way he can exeute the will directly in the name of grand chidlren. If it is like so then father of the son will be the minor guardian, it is the best way to safe gaurd the interest of the minors.

I agree with rajeev sir.

what Mr rajive has suggested is right and the safest way.. but as going through the intention from ur query.. that also could be done  i.e creating life interest in his children with a condition that they will not alienate the property and with disposition that ultimately the property will vest in the grandchildren(either on attaining thier majority or death of their parents... several case laws on this point.. if u need i can  provide u the citation..

Yes, he can.

Now Mr. A wants Mrs. B and Mrs. C to have rights on the property and after their lifetime the property to go to the grandchildren. Can he write a will to ensure this. What condition he should put to ensure this ? Also he does not want husband of Mrs. C to have any control over the property - how to ensure that?

As the property is self acquired property of Mr.A, he can write a Will. Under the WILL, life interest is to be given to both Mrs.B and Mrs.C that they can enjoy the property till their life time and then the property shall devlove absolutely on grandchildren. Since the Mrs.C herself is life interest holder and she can only enjoy the property without the right of alienation, her husband cannot do anything. No separate clause is required.