Wow! Your physical issues sound much more severe than I'd imagined, but I'm glad to hear that your progress has been so good! As you said, you must be getting unseen help-- although I think willpower and attitude are critical to healing (or for that matter to just getting through day-to-day life even if we're as healthy as a horse), so it's important for us to stay positive in the face of our obstacles and frustrations, and keep striving as best we can no matter how long and hard the road may be.
I did have this idea about creating song endings though. See if you agree. If I restrict recording to 8 tracks of instruments, I can use the other 8 tracks to duplicate the same instruments and create an ending and then copy the end created on the second 8 tracks to the applicable measures where I want the song to end. Does that make sense to you?
If I follow you correctly, that should be one way you could do it. However, I see from your other post that you found out how to insert events. Yes, you can insert measures-- see page E-76 of the manual-- and then you should be able to insert events into the new measures.
Speaking of the manual, do you have the PDF of the manual or are you just using the printed copy that came with your keyboard? If you download a PDF copy from Casio's web site--
http://support.casio.com/en/manual/008/CTK6200_WK6600_EN.pdf-- then you can use the "find" command (CTRL-F) to search for a word or phrase, which is a lot easier and faster than flipping through the paper manual hunting for something.
In MIDI an "event" can be many different things-- basically, it's a "command" if you will, and there are different kinds of commands.
Since MIDI is intended for playing music and controlling keyboards, the most common type of event in a MIDI file-- as you might expect-- is usually the "note on" event, which says which note to play and how loud to play it. (In MIDI terms, this is called the note's "velocity," since how fast you hit a key correlates with how hard you hit it, and hence how loud you want the note to be-- although in some "patches" the velocity might control something else about the note, such as the filter cutoff or "brightness.")
Speaking of velocity, you can indeed adjust the loudness or velocity of notes, so you should be able to make your ending "fade out" as desired.
There's also a "note off" event that says which note to stop playing, but a lot of keyboards and programs just use a "note on" event with velocity 0 to accomplish the same thing, for reasons related to data compression (if there's a series of the same kinds of events without any other kinds of events in between them, the data can be squeezed together a bit-- so using "note on" with velocity 0 rather than "note off" allows the "note on" events to be squeezed together more efficiently). I'm going to use "note off" to mean an event that turns off a note, whether it's an actual "note off" event or a "note on" event with velocity 0.
In MIDI each event in a track is prefaced by a "delta time" that says how long to wait after the last event before performing the next event-- so the delta times of a pair of "note on" and "note off" events control the duration of a note. If I'm not mistaken, the Casio song sequencer doesn't show separate "note on" and "note off" events. Instead, you'll see a single "note" event that shows when the note should begin (the measure, beat, and tick), which note should be played (C4, D3, etc.), and-- I think-- how long to play the note (the note's "gate time"?). But if you look at the song data in a DAW's MIDI editor then you'll see the separate "note on" and "note off" events, which is why I've mentioned it. Also, be warned that a given "note off" event might not directly follow the "note on" event that it's paired with, since you might play a note or chord and hold it while playing a sequence of other notes.
Fortunately, DAWs have other ways of editing a song besides editing the individual MIDI events, such as a "piano roll" editor, or a "score" display that's like printed music. Usually you don't even need to look at the MIDI events unless you just want to see what they look like, or occasionally if you need to insert some special "SysEx" ("System Exclusive") command for the keyboard, or if you want to manually "fine-tune" the parameters of an event.
Another common type of event is a "program change"-- usually paired with a "bank select" event-- that says which "patch" (or "tone" in Casio's terminology) should be used to play the notes that follow. But there are many other kinds-- events that set the tempo, events that control the amount of reverb or chorus, events that bend the notes, etc. There's a list of event types that the Casio song sequencer uses on pages E-82 through E-84 of your manual.
I don't have FL Studio, but maybe I'll download the trial version if there is one-- otherwise I might not be able to help you with it except in the most general way. I know what you mean about the screen display-- the first time I started up Ableton Live Lite 8 I felt so overwhelmed by it that I promptly exited the program and went back to using the SynthFont DAW, which for some reason didn't scare me as badly.