there are no limits on the amounts you can loan. no interest needs to be charged if the total for the loans to this individual is $10,000 or less. otherwise, just charge adequate interest. otherwise, you run afoul of IRC Code Section 7872. see this article for guidance.
https://www.investopedia.com/terms/a/applicablefederalrate.asp#:~:text=Which%20AFR%20rate%20to%20use...
for the AFR rates see this link
https://apps.irs.gov/app/picklist/list/federalRates.html
