Both of your quoted bolded portions include an important word "income". If there is no income, there is no impact on SSI. Selling used things very rarely generates income since used things usually go down in value. A graphics card right now is one of the few used things that could generate a profit. But the simple solution is to just sell it for no more than what it was purchased for. Thus: no income and no SSI impact.
So, if he kept the receipts or has some other proof of value, he's supposed to be in the clear. But I still can see a scenario in which some antique would cause an issue. But yeah, if he got the receipts, he just has to do more paperwork.
Let's say I had payouts totaling $20k, but the cost I spent on said inventory was $21k, how do I report this? Thank you in advance for any help or guidance.
community.ebay.com
.
Sometimes the government makes trouble anyway. They come around and reduced my mom's checks(retirement) by a dollar, even for just switching from paper checks to direct deposit.
In general, if a vested party has an interest in preserving their stash of money or some other action they prefer doing(such as cops not investigating shit), they'll claw for any tidbit to justify taking a cut.