What qualifies as a dependent?

Many factors are considered.

Please use this dependent test from the IRS to determine qualification.

https://www.irs.gov/help/ita/whom-may-i-claim-as-a-dependent

This article will provide more information on dependents.
https://ttlc.intuit.com/replies/6514582

The IRS has an interactive tool that will guide you on who can be claimed as a dependent.
https://www.irs.gov/help/ita/whom-may-i-claim-as-a-dependent