Only a ring bearer - where does he stand?

I'd have him sit with your mom.

It depends if you're doing anything else with him during the ceremony. I'd keep him with you until that was over then have him sit.

If you wanted him to stand I would put him standing next to your FH.

He'll probably want to stand with you. And that's fine.

I think you could go with any of those options, whatever he is more comfortable doing. But if you decide you want him to stand up with you, I would have a seat for him by your mom in the front row just incase he gets tired or antsy standing there.

Let him stand with you or FH as long as he wants, but have a seat for him with your mom. Our WP kids are standing as long as they feel like it, but we have moms and grandmas on standby to go sit with or take them out if necessary (church wedding.)

I didn't have an RB, but 2 FG's and we had them sit during the ceremony. Kids get antsy and we didn't want the possibility of that distraction. I made sure both of their mothers had a reserved seat on the first or second row of either side on the aisle and they were instructed to walk and throw the petals up to the end of the aisle and then separate to go sit with their moms. From what I hear, it went just as planned