Is there travel assistance for mentally disabled people?

I have severe, crippling anxiety and am also autistic (on the higher functioning end but autistic nonetheless) and might be flying both alone and internationally for the first time next year. In all honesty I don't think I could manage this form of travel alone but I don't have much of a choice and it got me thinking, are there any kind of programs or something that provide help for mentally disabled people to travel successfully?

I know it's a stretch but honestly if I could just have like a "travel buddy" assigned to me to help me navigate the airports properly and give me direction I'd be golden lol.

Why do airlines charge you for picking your seat?

It's so stupid. Airlines like American Airlines and Delta and wonder why should i be charged for claiming a seat ahead of time. And they'll tell you to upgrade your ticket at a higher price just so you can have extra benefits such as Overhead bin access, Choose your seat and
Ticket changes for a two hour flight. This is highway robbery.

Missing my flight on purpose?

I recently booked a flight from Orlando, FL to New York to see my family. The flight from FL is American Airlines and the flight from NY (back to FL) is Delta. Seeing how I wasn't too sure of my family's availability, I got the insurance just in case. Turns out the insurance is a bunch of bs and can only get a full refund for certain reasons with much documentation and proof (not even going to bother).

Therefore, I'm thinking of missing that flight on purpose and just rescheduling another trip. I was thinking of rebooking it but the change fee is $200 and I can just get a new round-trip ticket for much less. So my question is, if i do that, is there a fee the airlines would charge me for missing the flight or it doesn't matter? I've never missed a flight in my life so not sure.

Where should I exchange Dollars to Pesos?

I'm going to Mexico in June and heard the exchange rate at the Mexico airport isn't good so what bank here in United States in California should I exchange dollars to get pesos, where's the best bank that give the best rate?

I want to take cash to Mexico what's the safest way?

I'm going to Mexico around June and I'm gonna take a couple thousand dollars with me, I'm not going to put the money in the atm or cards because I want to exchange the money in the Mexico airport there I get the pesos, I will probably take two wallets in my pocket and dress to blend in and not attract attention, I've traveled alone once but traveled to Mexico by plane around 20 times I know how everything works, but what's the safest to take the cash