ABS and other lights constantly on

In Feb 2017, I helped my uncle buy a used 2011 Prius with 135k miles on it. A month or so ago during oil change, the Toyota dealership mentioned that it's spark plugs need to be replaced. To save moolah, he took it to a local mechanic to replace spark plugs and radio (not sure why he wanted it replaced).

Since then, a few dashboard lights have been constantly on (see attached photo). Also, the screen in the middle with GPS / radio / climate controls has gone almost black. I say "almost" because if we look very closely, we can see that it is actually working.

Any idea what's going on and how to fix it?

Thanks so much in advance!