Regardless of whether audio "brain healing" is an actual thing, you can use steady and modulated frequencies to induce mildly altered states of consciousness. Some people experience these states as pleasant, others as unpleasant. Either way, the effect is subtle enough that you probably won't be able to consciously detect it unless you are an experienced meditator or have otherwise made an effort to develop an awareness of subtle mind states.
FM synths are a great way to play with these frequency effects. You can start out with sine waves and easily dial up and down the harmonic content. Ableton's Operator is perfectly adequate for the task, as is NI's FM8. The classic Yamaha DX series are also good choices, but you will want to look for a six operator synth like the TX802 rather than the four operator synths like the TX81z. The thing to look for is fine grained control over frequencies and envelopes - this is present in the six op synths but tends to be dumbed down in the four op synths. Also, the button pushing interface gives you very precise control compared to on-screen faders.
There is not much on this except for a few esoteric sites which I am skeptical of.
In my experience, this is a very subjective area. Run some experiments on yourself to see if you notice anything. If you don't, then work closely with the installation artist to get it right. I wouldn't bank on any medically-verifiable healing going on, but mild and pleasant trippiness is very possible.