Is it wrong for grandparents not to attend the Nikah and Walimah of their grandchild?

Answer

There is nothing wrong even if the father is not present at the Nikah of his son or daughter. Nikah in Islam is a simple 5 minute act. A Walimah is also a simple feast organized at the home of the husband. A handful of people, including a couple of very poor persons should be present at the small unostentatious meal.

The huge feasts which are organized today are not Walimahs. These customary practices are functions of pride and show. Therefore, even parents should not attend these mock 'walimahs' if indeed they believe in Allah Ta'ala.