Not open source software development, but if he wants to continue helping folks with a different area of the US tax code there are the Volunteer Income Tax Assi

Not open source software development, but if he wants to continue helping folks with a different area of the US tax code there are the Volunteer Income Tax Assistance and Tax Counseling for the Elderly programs[0]. Not sure how COVID has affected the programs. It would provide an opportunity to meet and help folks in his community. In a more software development type idea, there is a guy that maintains http://excel1040.com http://excel1040.com, which is a free spreadsheet to calculate US personal income taxes. It doesn't handle everything, but it handles quite a bit and provides a version early in the year to estimate your taxes. Something like that for imports might be an interesting project for him. [0] https://www.irs.gov/individuals/irs-tax-volunteers https://www.irs.gov/individuals/irs-tax-volunteers