My uncle is having a Green Card which was issued in 1980 with no expiry date on it. due to some family problems he came to India

If his I-551 is white, and it has no expiration date, then it is still valid. The challenge is whether the CBP believes he has abandoned his permanent resident status in the U.S. Also, whether he can somehow prove that he did not. The process of being admitted is complicated.

There may be ways in which he can again qualify for an immediate visa. This can take time to discuss and explain.

I strongly recommend that you schedule an appointment or teleconference with a candid and experienced immigration attorney like our office.

The above is general information not meant to be legal advice. The above reply does not create an attorney-client relationship.