Is it possible to control two brakes from a single lever? Up until the start of the year, I was a keen road cyclist, I even dabbled a bit on here amongst the experts, but unfortunately in February I suffered a stroke.

I am gradually starting to pick things up again, one of which is a desire to get myself riding once more.

The stroke has left me with some damage, in particular it has paralysed my left arm and left me very unbalanced(!). I'm hopeful that maybe converting to a tricycle will help with the latter, but I have a question specifically about the former.

For the sake of this question, the bike I'm thinking about converting is about 5 years old, has brifters and dual pivot rim brakes. It shifts mechanically.

Now, I figure that it might be possible to rig something up, so as to allow me to operate the front derailleur with my right hand. An inventive use of a bar-end shifter, perhaps? But I'm at a loss as to how I can get the bike to brake smoothly, operating both front and rear brakes at once. One solution I can think of would be to control both brakes with the same brifter, and I was wondering, is this even possible in practise?

Also, I'm aware that an easier option, given my disability, might be to use an electronic shifter. In this scenario, I wouldn't even try to modify the existing bike, but would instead buy something new. But of course, current fashion dictates that new bikes commonly ship with disc brakes, and so I have a secondary question regarding how I might do this with hydraulic disc brakes. (Presumably, with mechanical disc brakes, the approach would be the same as for dual pivot brakes?)

Please note I'm not looking for a product recommendation here - I'm quite capable of doing this myself - but if someone can say "Yes, I've seen it done", and maybe suggest some search terms, then I would be grateful. As things stand, I'm not even sure what to look for.
Glad to see you're back!

You can use a Problem Solvers Cable Doubler 1:2 to pull 2 brakes with 1 lever. Its a little device which you hook up the two brakes to (assuming they have the same cable pull) with 2 sets of brake cables, then run something to the levers. This works for essentially any pair of cable operated brakes with the same cable pull. 

For hydraulic brakes, there are some lever mounting strategies here, but I'm pretty sure the obvious solution (using a Y-splitter in the hydraulic line) won't work. 

You also might want to look at this question for general one armed cycling stuff. 

As for shifting, a bar end shifter is probably easiest, or shimming a thumb shifter. Depending on how your strength is distributed, an interrupter lever might be useful as well.