The website states -
The third payment included up to an additional $1,400 for each dependent you claimed on your 2020 tax return (or your 2019 return if a 2020 return had not been filed or processed) with a valid social security number (SSN) or Adoption Taxpayer Identification Number issued by the IRS. A valid SSN for the third Economic Impact Payment is one that is issued by the Social Security Administration on or before the due date of your tax return (including an extension to October 15 if you request it). An individual was your dependent if he or she was your qualifying child or a qualifying relative.
The website goes on to describe who is a qualifying dependent. Either a Qualifying Child or a Qualifying Relative. Your dependent probably is eligible under the Qualifying Relative rules
What you posted is if the dependent was a Qualifying Child. It goes on to describe who is a dependent under the Qualifying Relative rules:
A person was your qualifying relative if the following conditions were met:
- The person can't be your qualifying child or the qualifying child of any other taxpayer.
- The person either is related to you in one of several ways or lived with you all year as a member of your household (and your relationship must not violate local law).
- The person is a U.S. citizen, U.S. national, U.S. resident alien, or a resident of Canada or Mexico.
- The person's gross income for the year must be less than $4,200 for 2019 tax returns or $4,300 for 2020 tax returns. (Exceptions exist if the person is disabled.)
- You must provide more than half of the person's total support for the year. (Exceptions exist for multiple support agreements, children of divorced or separated parents, and parents who live apart.)
- The person doesn’t file a joint return for the year (or files it only to claim a refund of withheld income tax or estimated tax paid).
