Can relatives immigrate to the United States?

It is possible in theory, but it is basically impossible in practice.

The immigration route is:

1. Your grandfather (if still alive) applied for your grandfather, your grandfather applied for your father, and your father applied for you.

When it's your turn, it's estimated that it will be at least forty years later. In every process, the applicant must be alive.

2. Your grandfather's children (that is, your grandfather's half brothers and sisters) apply for your grandfather, your grandfather applies for your father, and your father applies for you.

According to this timetable, wait until you estimate 50 years later.