You have not told us anything about your cousin so we do not even know if you can claim your cousin.
IRS interview to help determine who can be claimed:
https://www.irs.gov/help/ita/who-can-i-claim-as-a-dependent
https://ttlc.intuit.com/questions/3113432-who-can-i-claim-as-my-dependent
WHO CAN I CLAIM AS A DEPENDENT?
You can claim a child, relative, friend, fiance (etc.) as a dependent on your 2018 taxes as long as they meet the following requirements:
Qualifying child
• They are related to you.
• They cannot be claimed as a dependent by someone else.
• They are a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
• They are not filing a joint return with their spouse.
• They are under the age of 19 (or 24 for full-time students).
- No age limit for permanently and totally disabled children
• They live with you for more than half the year (exceptions apply).
Qualifying relative
• They don't have to be related to you (despite the name).
• They cannot be claimed as a dependent by someone else.
• They are a U.S. citizen, resident alien, national, or a Canadian or Mexican resident.
• They are not filing a joint return with their spouse.
• They lived with you the entire year.
• They made less than $4,150 in 2018
• You provided more than half of their financial support. More info
When you add someone as a dependent, we'll ask a series of questions to make sure you can claim them.
Related Information:
• Does a dependent have to live with me?
• What does "financially support another person" mean?
• Can I claim a newborn baby?
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**