Time through customs at Gatwick

Customs is a walkthrough. Immigration is the variable. I've seen hour plus waits at Gatwick as well as easy transit through. Its almost impossible to tell.

There are two terminals so meeting will depend on which terminal each of you arrives.

Thanks Frank II, I arrive in the North Terminal. My brother will try and find out which terminal Orly to Gatwick lands in.
Do you think 2 hours post arrival for a meet time would be reasonable?

The rail station is reached via the south terminal. So perhaps have a look at the airport map and find a suitable meeting point there?

The Wetherspoons bar The Flying Horse in the South Terminal would be a good place to meet
Its on an upstairs level overlooking the concourse not far from station entrance

my experience is that Gatwick can be a breeze or take an age.

Your brother will also have immigration (UK not in the EU nor Schengen).

I might have met at the Sofitel. Comfy chairs, expensive but good food...

You'll both have phones?

Change of plans….my sweet brother and SIL are now taking the Eurostar from Paris to St Pancras. He is STILL willing to take the train out to Gatwick to pick up his little (and favourite🥰) sister before the 3 of us head to Reading and switch to Bath train. That adds hours to his travel. Which would be easier, for me to meet them in Reading and continue to Bath or to meet in St Pancras? Maybe there’s a nice pub just outside either of those stations that we could meet at. That way nobody is sitting on a train platform waiting for the other party.
Yes Nigel, we will have phones. I’ve never had a phone with me in Europe before, but I understand there will be some place at Gatwick where I can purchase a SIM card that can be put in my phone.
Thank you all for your suggestions. I would really appreciate suggestions for this new meet up.

Take the train to St Pancras and meet at the statue

https://en.wikipedia.org/wiki/The_Meeting_Place_(sculpture)

Thank you all for your great suggestions. We’ve decided to meet at Reading and go to Bath from there. After getting some cash from a machine and finding a SIM card, all I need to do is take the shuttle from the north terminal to the south terminal and head to Reading. Any landmark outside Reading like the statue at St Pancras?

I think of this as a hassle after a 7 hour layover in Vancouver and a 9 hour flight. You’d never guess that in my 20’s I spent 2 years travelling around the world by myself with a little bag, no phone, and an inherent trust that nobody would rip me off. Nobody did. Travel hasn’t changed, but I’ve gotten older.

I'm glad you have found a solution that works for you.

I would have done it differently - your brother and SIL will arrive rested at St Pancras after a comfortable ride from Paris, you will be exhausted after the extensive flight combination you outlined.

I'd have done as I thought above, both of you head for the comfy chairs at the Sofitel - even if either or both of you have phone problems it will be so easy to meet up and be comfortable. It is only 45 minutes to just about an hour from St Pancras on the Thameslink to Gatwick, and the Sofitel is so easy to find. Meet up, have a reunion drink (tea, coffee or something from the bar), and all head together for the train to Reading and onwards to Bath. You'll all be together and can chat the whole way.

I haven't been to Reading since the refurb but that station has always been at the very bottom of my list of stations to do anything at. When I used to have to go there they used to have ghost trains - show up on the screen, time passed, and they fell off the screen. Or changed platforms. I hated the place. But it has been a few years and they may be better, I don't know of a current meeting spot there....

I wish I was able to meet up with my brother and his wife and daughter... you're lucky.

Thank you Nigel, for your considerate response. Maybe we will go back to your original suggestion. Having someone accompany me in my Zombie state sounds like a good idea. Brother Ted and I will have to revisit our plans.