As has already been pointed out numerous times in this thread, most popular does not mean best. If most popular were best then presumably Kenny G would be the best jazz artist and Justin Bieber would be the best pop artist. I'm sure we all know that's not true.

Emulating FFVII really can't be compared to the original graphics of the game because there are all kinds of filters that increase the resolution and otherwise improve the appearance of the game. The original polygon graphics look terrible. The pre-rendered backgrounds and FMVs are the only unaltered parts of the original game that have aged well. Even then they are trounced by FFVIII and particularly FFIX's (which are rivalled by Chrono Cross' as some of the best of the 32-bit era).

It sounds like your brother simply doesn't appreciate good sprites. As far as 16-bit graphics go FFVI's were some of the best of the era. A few games like Chrono Trigger and Seiken Densetsu 3 could be considered to have improved on them (they were also released a year after FFVI) but they certainly were better looking than anything that had come before them.

And I could easily turn the remake argument around to suggest that in recognising the game has a lot to gain from a remake they acknowledge its flaws by suggesting that there are things to be improved upon. That said there certainly is no shortage of people wanting a FFVI remake as well. One thread speculating on the possibility here received thirteen pages, and it's hardly the only one to have plenty of people expressing desire for one.