Hello

In Telangana, local reservation is usually decided based on where a student studied for at least 4 consecutive years before the qualifying exam (like Intermediate).

Since your son studied Intermediate in Telangana, that helps with local status.
But authorities mainly check the last 4 years of study before Intermediate.
If he studied those 4 years in Telangana, he could be considered a local candidate. If not, eligibility may depend on parent residence or other rules.
It is best to check the official admission guidelines of the specific university or exam.