My brother-in-law got that 55" Sharp TV on the Black Friday sale for $299.
After he had me come look at it, I was able to convince him what a POS it was and to return it. He got a slightly smaller (49") LG for $399 (still 4K).
It was obvious the picture quality difference, even thou we are talking cheap TVs here.

I didn't get to the point of testing control protocols on it. But I do know some newer Sharp TVs do not respond to all commands. But it should respond to some from the IR database.

Any chance your brother can take that POS back?

[edit]: Just looked in one of my customer files that I know has a newer Sharp. Not that exact model but power on/off codes work. No input codes worked. But that Sharp had a drop down input menu that shows when the input command is sent. A short macro is all that is needed to get to the input needed. It worked every time testing.