All other conditions being equal, hard or rejuvenation pruning of a rhody only controls size.

Without photos of your plant to illustrate the problem, all we can do is suggest making sure you are providing the conditions it prefers: a suitably acidic soil pH, a shallow planting (avoid piling mulch over the root zone), soil that drains properly, adequate irrigation during dry periods (especially in summer) and avoidance of late afternoon heat or reflected heat from planting too close to a structure.

Thanks so much for the reply. The time to do a rejuvenation is coming up, so I need to determine if it would be worth it.

Afternoon sun is the only thing we can't really correct and the large lower branch that died off was the only one hit relentlessly (though I still think that was a fungus). Anyway, this rhododendron has been in this position for 50ish years in the same conditions. We tried one year to come up with a shade screen but it didn't work.

We had un-idyllic soil ph of 7 when we moved in, when the plant was bushy and happy. We have only managed to lower ph very slightly (a tick or two under 7) despite trying for years with recommended amounts of sulfur and acid-loving plant fertilizer like Hollytone that shouldn't burn the roots, which are very shallow.

We had a soil analysis done early in the pandemic that basically said its soil was depleted of every important mineral. There's so much clay. We use compost and pine needle mulch on this. I am new to gardening and I know there's one theory that less is more when it comes to rhododendron care and that's not what I've been doing. But it is hard to be new at gardening because so much advice conflicts the other. I've so far tried to stick with the guy at the nursery when at odds because he has many of the same old plants I do.

It's on a hill and drains well-- too well -- though we water regularly. The trunk is much further up the hill than what the pic would suggest. It has grown forward to lean into the sun, I think.

From what I have heard, the previous homeowner had gotten on in years. The neighbors adored him and pitched in to work the front yard flower beds, but I doubt this plant got attention for a decade except for All Purpose Miracle Gro I know he used. Heck, maybe I should use that and stop thinking I can do better. (by the way, yes, I would hate for the neighbors to think I haven't tried hard to save their friend's treasured plant)

Here it is in its heyday 3 years ago. Leaves on today's pic are especially droopy because of the cold temps, not whatever ails it - that droop is much more mild. A couple of the leaves are a bit yellow and one or two today have some red rust spots -- that's new this winter, I had been treating with copper during spring and into summer. But I still have no idea of the overall problem.

I do realize now, too late for this season, that you're supposed to deadhead. That one's on me. :)

today is cold so it is extra droopy from the temps. I'd estimate when looking at it on a good day, it's only about 60%-70% as bushy as it used to be, plus we lost the lower branches to die off.

so leggy on the bottom half that I'm not sure what would be left after a significant pruning. Most of the pictures online show people still left with a recognizable plant afterward, not a veritable stick like I would be.

Thanks again for your time and advice!