I just hit the example sentence for 酒好き, and I think Wanikani may have taught me a new grammar structure. I want to make sure it applies as broadly as I think it does though.
The sentence Wanikani provides is for that vocabulary is: 私の妻は酒好きなので、アル中にならないか心配だ。(My wife is a drinker, and I’m worried about her becoming an alcoholic.)
Can the end of that sentence, taking the structure of “~ないか心配です,” be applied to any situation in which the speaker wishes to express a worry about something happening, where the event proceeds “か心配です” in its negative form? Or is that going to sound awkward in cases where the verb isn’t なる?
「間に合うか心配」という日本語は「間に合うかどうか心配」という意味ですが、「間に合わないこと」を心配しているので必ず否定文になります。[…] そして 日本語が否定文になってない ので英語を「I’m worried I’ll make it.（間に合いそうで心配）」と否定文にし忘れる人が多いので気をつけましょう。
So it doesn’t need to be in negative, and when you have something like 「アル中にならないか心配」, that’s basically the same as saying 「アル中になるかどうか心配」: “I’m worried about whether or not they’ll become and alcoholic”.
In that particular case, putting the negative makes it clearer what the speaker is concerned about, but you could make it more general. So the pattern is more 「～か心配」, with a verb phrase in place of the 「～」.
Well that ～ないかと心配です isn’t grammar point on itself, but sure you can use that to say you’re worried about something like 遅刻するのではないかと心配です - I’m worried that I’ll be late. The key thing is that ～ので○○ないか○○ -structure there. It gives it a more of a “I’m afraid whether or not I will be late.” -kind of nuance, similar to どうか.
Providing this as an alternative makes a ton of sense. I was assuming か in the example sentence was a question particle in exactly that vein, but it’s nice to have confirmation and some alternative structures. I can see how the conjugation in that case is less of a strict requirement. It’s basically the same as any embedded-question structure, then, but appended with 心配です/心配する instead of “知りません” or something like that.