What taxes must a US citizen pay

[Pacun]

Let's say someone lives in El Salvador and he is a sole proprietor but has employees.  He makes clothes using local materials and selling them locally. His payroll is prepared in El Salvador and at the end of the year, he reports his income in a form called Schedule C ElSalv.  He lives in El Salvador with his US citizen child age 14. In 2020 his income was $60K and for 2021 was $300K. 

No tax treaty between the countries and he is Head of Household. Does he have to pay SE taxes? Will the child get only $2,000 Child tax credit. Will they both qualify for stimulus 1 and 2? Can they exclude income for both years but pay SE? Any information or suggestion will be appreciated. 

[Lion EA]

Is he a US citizen/green card holder? I know a couple of the answers. He DOES pay SE tax (can exclude only income tax.) He can take the FEIE OR the FTC, but not both; you'll have to look up the income ceiling on the FEIE. You probably deal with more US citizens moving out of the US than I do. (My one family of citizens living/working in Singapore qualified for AOC for one daughter going to college in the US, but the other daughter attended a non-qualifying school in Europe for a couple years before transferring to a qualifying college for her junior year.)

[TexTaxToo]

The child qualifies for the $3000 CTC, but only as a non-refundable credit.  If not enough taxable income to take the full $3000, up to $1400 can be taken as refundable ACTC, as in previous years.

All the RRCs (stimulus) are available to anyone with an SSN valid for work, regardless of where they live.

This assumes they meet the income limits and other requirements.

[TexTaxToo]

DIdn't edit it in time.  With an income of $300K and HOH, the entire CTC and RRC would be phased out.