disown son from self acquired property

You can gift your self acquired. Property to whom you wish .

If you give gift, it should be by way of Registered Gift Deed. When you gift the property, from the date of it's Registration, you shall not be the owner of the property. Once it's the property of the children,  to whom you gifted, they can do whatever they want to  including mortgaging or even sale of said property.

Therefore, think before you lose control over your property.

If it is a will, Registration is better to avoid later complications, the property control shall be with you only,  as long as you live.

During your lifetime, you can deal with your property at your discretion.

Draft a partition deed excluding the son and register it in sro which is easier,let he question in court as you are owner you have right to give partition as per  your wishes along with possession .

you didn't mention your age.

If you dont want to give any share of your self acquired property to your son, daughter-in-law and grand child, you can give it to me as gift. I will take it happily..

Good suggestion and another choice. 

Another choice is to donate it to old home, Trust or to Govt

Donate or sale the property to whom so ever you wish.

Will can be challenged after death.

A word of clarification on my one liner above.

When I wrote  " good suggestion " I was referring to the suggestion given by  Shri Shashi Dhara.