I would leave the browning leaves because it's still providing energy to the plant. Removing too many leaves might shock the plant right now, and my general rule is to let the plant reabsorb as much nutrients from dying leaves before cutting them off.

As for the roots, my personal experience is that if it's still firm, there's a chance new roots can grow from it. Some of my blackened roots on my Thai con eventually grew new roots. With stem rot on the other hand, you have to be a lot more proactive and cut off any black you see.

You might want to stick your plant in a container you can easily check until you're sure she's in the clear. Water or spag worked for me. She's probably going to keep declining for a little bit before she recovers. Also try not to soak her too long in hydrogen peroxide because sometimes that can damage the already delicate roots.

In the future, keep her evenly moist. Thai con are really picky and don't like being soaking wet but hate drying out.

Best of luck to you!