Only the Lonely

Riding my bicycle is a personal thing.
I don't actively pursue riding partners or company and I have never had anyone ask me to join them on their ride. Until now.
My brother is in training mode for an upcoming triathlon and he recently asked me if I wanted to ride with him. Tri geeks it seems, like to train alone.
Sure! was my response. Then I put some thought into the scenario.
First some backstory:
My bro has been doing triathlons for some time now. He also did the Honolulu Marathon. As you can imagine, although he is younger than I am he is looked up to by me because of his accomplishments and the fact that he has more money than I do.
Despite the differences in our biking interests, I have often gone to him for equipment and "training" advice. The word is in quotations for I don't think you can call what I do on the bicycle training. Thing is, he is not a year round rider as I imagine myself to be so our fitness levels differ depending on the time of the year.
I know the route they ride for their forty kilometer TT. I also know his time.
Now, about riding with him.
He rides on his aero rig so he doesn't have brakes.
So, who leads and who follows? Depends on who is faster right?
Now, would it be fair to him if I let him draft me? After all, he is the one training. This would assume of course that I am at least as fast as he is.
If I am slower, is it good form for me to ask him to slow down? I think not.
Maybe I'm making too much of all this; I mean if he is anything like me (and he is definitely not) then he probably thought of all this too right?
Well, if he is anything like me (and he is definitely not), then he probably enjoys riding alone.
Riding by bike is my time to get away from other people. It is my time to concentrate on me and me only. It is time to think about cadence, speed, tempo, position and technique. After one year on the bike, I am finally getting my pedaling stroke down.
Cycling is a concentrated effort for me. It is about seeking my very own piece of cycling perfection. It is about bringing out the rider in me and not about the rider I think I should be. Does that make any sense? Well, you get the idea.
So anyways, I am thinking about going for a ride with my brother. It's not like I don't see him often (I do), it's just that we don't get to really do things together too much anymore. As opposed to when we didn't really do things together anyways.
I don't know why this is causing me so much trepidation! I mean this is supposed to be fun right (see below)?
Now I am beginning to make up plausible excuses: it's too far of a drive to meet him, his riding time is different from mine, his ride is too long/short, I don't want to ride in the evening, etc, etc.
The thing is, I just don't think I want to ride with someone during the time I take out to ride alone. I like to eat alone also, so what can I say?
Well, I'm supposed to call him next week and I'm still not sure what to do.
Oh, and I was so excited about the oppurtunity that I even offered to ride my display bike (see below) so that I would at least be able to keep up with him.
Leave the road bike at home, he says. Bring the 29er.
What the hell is that supposed to mean?