This article is about Long Covid, so in a sense this is circular evidence.

Nonetheless, the two qualifiers in the statement "People who had severe illness with COVID-19 might experience organ damage affecting the heart, kidneys, skin and brain" weakens the argument. If the long-covid issue was just that people who were in ICU then had long-term symptoms, that's an easy premise to understand. But IMHO, for mild symptoms, there's a non-obvious leap to say that long-term brain damage somehow occurred.