Since this is a "medical" and as such might be a temporary need, and you say you have no desire to run more than one head at a time, the simplest and least invasive would be to replace your existing shower head with a hand held retrofit kit.

Yes, you can buy additional brackets so the head can be mounted elsewhere on the wall. And you are correct, the bracket needs to be matched to the head, they are not necessarily universal.

A lot of showers I build, I also make a teak bench for them. In addition to an extra bracket or two on the wall, often times I'll add a bracket to the edge of the bench.

I'd look for the longest hose you can find. Personally I find the segmented metal hoses lay flatter and loop over themselves less than the plastic hoses.

Plastic versus metal head? Plastic is fine in a decent head, but in a $9.00 head the entire thing might be too lightweight and spray water everywhere regardless of what material it is made from.

Mongo

Thanks, Mongo! Lots of great and useful info. One more question: If we decide to go with a metal head, is there a particular brand or two that you would recommend? Thanks again.

I don't differentiate between metal and plastic since they can both be cheap pieces of trash or well constructed units.

I probably install more Grohe and Hansgrohe than any of the other brands.

I've had the Grohe Relaxa Plus Top 4 (which I think might be discontinued?) in my own master shower for several years. No complaints, excellent performance, no quality issues, and it has been dropped a couple of times over the years. It's plastic.

Mongo

The Grohe Tempesta shower head is metal and has a silicon ring edge to prevent damage if dropped. I've never dropped it, so I don't know how well the silicon works to prevent damage, but I do like the shower head.