First off welcome to the forum. Do you have many Hoyas? You do know lurking around here can cause you to dramatically increase the number of Hoyas you grow. I used to be really into orchids, mainly Bulbos and Angraecoids but now I think I might have more Hoyas than orchids.

I have only had my Hoya paziae since the spring but it has proven to be a fast grower. Because this species has thin leaves it is not as resilient as the succulent leaved species. It sounds like the leaves are dehydrated and that can only mean that the root function is impaired. What kind of potting mix are you using? I would suspect root rot but from what you have mentioned it sounds like you have the problem diagnosed correctly. Some Hoyas are sensitive to having their roots dry and they may die, did this plant ever become dry by accident?
I would take cuttings and root them in a high humidity environment like a freezer bag or a rooting aquarium. Spraying the leaves frequently with water might help them rehydrate while roots form.
Hoya paziae is a species that grows at mid elevation in the Philippines so it does not experience overly hot temperatures in nature and the combination of heat and sun may have stressed your plant. I grow my plant in a shaded south window (sheer curtain + other plants) and today the light meter reading is 6300 lux or 585 foot candles, not very bright. The temperatures in my plant room do get quite warm but not higher than the upper eighties Fahrenheit.

Some growers use semi-hydro exclusively but I don't grow any this way. I am sure someone on the forum can help and if you can grow orchids in SH you can surely grow a Hoya that way especially if you start with a cutting.

Mike

Mike thank you for the welcome.

I have about 25 Hoyas now, and use orchid seedling bark mix to pot them in. As for the orchids, I have a variety, but focus mainly on Dendrobium species and Catasetum alliance plants. It would be a while before the Hoyas outnumber the orchids, but it is possible. lol

I don't think I allowed the paziae to dry, as I'm out watering everyday, as many of my orchids are mounted, and I check all the other plants while I am watering them, but it is possible.

As for the cuttings I already took, they do look like they are starting to root, and the leaves on the cuttings are looking better than the leaves on the main plant. Now the cuttings are inside, where it is cooler - so with that and reading your info on the plant's natural habitat, I'm going to bring the main plant inside as well today and also take a few more cuttings. Our temps here have been extremely hot lately, but luckily all my other Hoyas have responded well to it with amazing growth this year. Even the H. serpens.

I am glad to hear that the cuttings are doing well, at least this is a fast grower and you will have a nice sized plant again fairly soon.

Mike