"He helps you every day"
Translation:Anawasaidieni kila siku
Yes, this is the plural form: -wa-...-(e)ni is the plural you as an object. The -(e)ni is there to disambiguate it from "them".
I would have said anakusaidia kila siku or maybe yeye hukusaidia kila siku because I'm not a mind-reader and there's no way to tell from the English that they want a plural answer. Please make a report if you do this lesson again. Give an answer with -ku- and click "report" > "my answer should have been accepted".
I don't think 'wa' and '-eni' need to both be used. 'Wa' is already indicative of plural "you". '-eni' is used in the imperative for the same reason