A taxpayer can generally claim a personal exemption for an unrelated person if they meet the income, support, and citizenship tests. However, the person must not be living with the taxpayer in violation of local law by living with you.
The parents reduced their taxable income by $3,650 by claiming a personal exemption for an unrelated person. Since the parents income was taxed at the 30% tax bracket, the income reduction may decrease their income taxes by $1,095 ($3,650 x 30%).
If you are in a combined (federal, self-employment, and state) tax bracket of 30%, you could reduce your taxes up to $300 for every $1,000 of income reduction by claiming a personal exemption for an unrelated person.