I'm not familiar with that form and that credit. You may want to do a new post to attract an expert in that area.
That said, I did a quick peek at the form 8962 instructions. It seems to say no, you do not include his MAGI, since his total income (8000 +2200 = $10,200) is below the filing threshold of $14,600 (2024)*.
"Household income.
For purposes of the PTC, household income is the modified adjusted gross income (modified AGI) of you and your spouse (if filing a joint return) (see Line 2a, later) plus the modified AGI of each individual whom you claim as a dependent and who is required to file an income tax return because their income meets the income tax return filing threshold (see Line 2b, later). Household income does not include the modified AGI of those individuals whom you claim as dependents and who are filing a 2024 return only to claim a refund of withheld income tax or estimated tax."
*Scholarships are a hybrid between earned and unearned income. It is earned income for purposes of the $14,600 filing requirement (2024) and the dependent standard deduction calculation (earned income + $450). It is not earned income for the kiddie tax and other purposes (e.g. EIC). For grad students and post grad fellows, scholarship, stipend and fellowship income is earned income ("compensation") for IRA contributions.
