My personal interpretation of this is slightly different. If I were translating literally, I would translate it rather as ‘the sort of existence/beings you are, doing what and for whom… never ever/really don’t forget.’ In other words, more idiomatically, it means ‘never forget what you are, what you do and for whose sake.’ (Obviously, the idiomatic version loses some of the emphasis created by the word order in the Japanese version.)
Did you copy that sentence with exactly the same punctuation as is used in the book, manga or anime (or drama?) you’re looking at? You sure that’s one sentence?
It’s been a while since I’ve seen anything like this, but if I remember correctly, this is an example of a question being used as a modifier…
Yeah, OK, I just dug through my message history with my fluent friend. I encountered a similar sentence from Shield Hero Volume 18 in August 2019. Here’s mine:
返事さえもまともにできないのか、絆は寝っ転がったままなので煙が充満する部屋から出る。
As if unable to give a proper response, Kizuna continued to lay around, so I came out of the smoke-filled room.
Similarly, your sentence means something like ‘it was a dream about being in the middle of the sea, as though it was/seemingly/perhaps a continuation of the daydream I had this/that morning.’ The use of a question (のか), along with な as the copula because you need something to replace だ after a noun, actually just adds a sense of uncertainty. You could replace なのか with である here, if I’m not wrong, but that would mean the speaker is certain that the sea dream is the continuation of the daydream. Using なのか instead indicates that the speaker is making a guess or relating what seems to be the case. In essence, the speaker has taken an ordinary relative clause – 「できない絆」or「である…夢」– and added an element of uncertainty.
To be honest, after you’ve seen usages like this a few times, you might start – like me – to think that か should be called the ‘uncertainty particle’ instead of just the ‘question particle’. That’s probably more accurate.