Get those plant out glass water and into soil they die in all water. When you transplant blackberries there no need try save flowers and leafs just roots and crown all you can save. Go plant them.

Long distance diagnosis is never terribly reliable, so I'd suggest you take a leaf and/or the picture to a local nursery that sells lots of rhododendrons - one shouldn't be hard to find in the prime rhododendron area of BC. In the meantime... The areas that look white are necrotic (dead) tissue. The brown areas will likely turn white after a time. The most common cause by far for this is exposure to winter cold, wind and sun. It's the result of mechanical damage rather than disease. The browning you experienced over the summer may have been a result of too little water. Same effect - dessicated tissue - but a somewhat different cause.

Mrs. T. H. Lowinsky "This plant has been around for a while and is still popular because of the striking and unusual blotch in the flower. A vigorous low growing plant, it blooms late with white flowers opening from lavender buds and a prominent orange brown blotch unlike any other. It has dark glossy leaves and is heat tolerant." [Rarefind Catalog] It is sold out at Rarefind, but a similar plant is Calsap. Here is a link that might be useful: Mrs. T. H. Lowinsky at Rarefind Nursery

Looks like they could be either 'Mrs G. W. Leak' or 'Mrs Furnival'. Both are tough (and common to our area) rhodies wth prolific bloom and similar coloration and markings. Mrs F tends to have a lighter blotch and blooms slightly earlier to Mrs L. Here is a link that might be useful: the Mesdames....