Paatti Sollai Thattathe
Manorama and S.S.Chandran are grandparents of Pandiarajan. He meets Oorvasi and marries her against the will of Manorama. Hence, he has to leave the house and goes to town. S.S.Chandran, who comes in search of Pandiarajan finds him with a boy and mistakes him as great grandson. This leads to problems in the family. How Pandiarajan solves these problems is the rest of the movie.
Starring Manorama, Pandiarajan, Urvashi, Silk Smitha, Disco Shanti, Kovai Sarala, S. S. Chandran, Y. G. Mahendran, Senthil, Anandaraj
Watch "Paatti Sollai Thattathe" on Amazon Prime released in 1988. It's a drama and comedy movie, and has a rating of 6.8 out of 10 from Imdb which is usually fine for this kind of movie.