So, I think this is confusing you because you are attaching the に
to くれる
and not 会う
. While that's a reasonable interpretation and you could certainly argue for parsing the sentence out like this: (私に)(会ってくれる)
, I think it will be easier to understand if you parse it like this: (私に会って)(くれる)
.
Concretely, the important thing is that while に
can be used to mark the recipient associated with くれる
, you can also attach くれる
to all kinds of clauses including those that have no に
or contain other uses of に
. For example, if we look at the below sentence:
友達が私の郵便箱に手紙を入れてくれた
(My friend put a letter in my mailbox for me)
This に
is clearly not marking the recipient of くれる
, as it's the speaker and not the mailbox who is receiving the favor here. If you can accept that the に
or と
in your case is attaching to the verb 会う
, either structure should make sense. You can read about the differences between に会う
and と会う
here, but if you want further evidence that both of these are reasonable you can see that there are plenty of Google search results for both に会ってくれる and と会ってくれる.
Some of the と
are conditional and a lot of the に
are either marking time or part of のに
, but if you scroll a bit you can find examples of both particles attached to people who are being met.
ペンを貸してくれられる
-- Did you mean to type 貸してくれる? We don't say くれられる. – Chocolate♦ Dec 24 '20 at 13:45