It is subjunctive -- in old spelling, there would be an iota subscript (upogegrammeni) under the alpha at the end. Just present subjunctive rather than aorist subjunctive.
In modern spelling, present subjunctive isn't distinguished in spelling from present indicative (e.g. we write να τρέχει rather than να τρέχη, with or without iota subscript) but I think it still exists.
"Can you help me?" translates to "Μπορείς να με βοηθήσεις(βοηθήσετε);" in Greek. And I agree with trezost, IMO and as given here refers to the present and asks for short-term in the moment assistance. That would be different if there was an explanation following, e.g. "μπορείς να με βοηθάς όταν μαγειρεύω; = can you help me when I cook?" (just an example lol)
"Will you be helping me? = Θα με βοηθάς (βοηθάτε);" is a correct EN phrase and sounds more natural to say when asking for long-time or lasting assistance. Even more correct when trying to translate the meaning of the GR sentence given I think would be to say: "Will/would you be able to help me?" or "Will/would you be able to keep helping me?".
Ok, first of all the Gr. sentence cannot be changed. So, we have to deal with "Μπορείς να με βοηθάς;
Which becomes in English: Can / Could you help me? and is correct. No, nuance of permanent or momentary or continuous. help.
Back translating from the English we have these choices ---Μπορείς να με βοηθήσεις/βοηθάς/βοηθήσετε/βοηθάτε These are the choices for the translation from the English. Which (except βοηθάς) is closest to the original Greek?