Simmons’ Gordon is expected to return in the solo Batman movie, whenever that’s released.
Regardless, Gordon’s worked with Batman through thick and thin, so seeing him with the other Justice Leaguers is a good sign that his ally is taking steps towards improvement.
Ben Affleck’s Batman has been fighting crime for over two decades, meaning he’s also been allies with Commissioner James Gordon for a significant portion of that time.
We know that at least one Robin died as evidenced by that memorial in the Batcave, but we haven’t learned yet what folks like Dick Grayson and Barbara Gordon are up to nowadays.