Hey there! Don't get discouraged! Is this RDWC or are each DWC bucket separate?
I'm sorry to tell ya buddy but that root situation is not looking good, at all.
I think your best bet is to give that plant straight water then throw it in the dark a couple days chop and reload unless that would interfere with your plans.
I think any time spent on this plant is going to be futile. I believe you said it is an auto. A couple things and this is only opinion based on observed results.
I love DWC, I feel like you are wasting the potential it has with the autos. Don't get me wrong autos are great for simplicity and beginners however they lend themselves to a preloaded soil of sorts. I'm guessing here, but as soon as those auto genetics ran into trouble and felt stress when you did the first flush they made their mind up and the whole plant just went into shutdown mode. In soil you can use this trait to your advantage but in hydro any slip ups in flower are going to be hard to get over.
Remember the extra cost in lighting and environmental controls for the flower cycle 20-24 vs 11-12 hrs to me it is not worth that ruderalis penalty on quality.
I think you can grow some monsters in that DWC, or some super fast turnover. GAS by capulator was finishing out 51 days flower. As far as those funky roots go, I would stay on top of my temps, oxygenation, and personally I would switch to jacks hydro nutrients. Cheap simple sterile.
If you are DEAD set on trying to rescue this plant maybe look into OG BIOWAR Root Pack
Cheers Yall