Strong’s indicates Hebrew cognates to Aramaic words, although in the Greek dictionary says “Chaldee origin”; but they are connected to the Hebrew cognates, the greatest likelihood being that they are loanwords from Hebrew brought to Babylon by the exiles.
Greek has distinct words for siblings and cousins (e.g. “adelphos” for brother and “syngenes” for cousin), whereas the ambiguity is in the Hebrew and Aramaic words, since it is dependent upon context; it is not likely that the Gospel authors made a mistake when using the lingua franca of the day.
That is why the Holy Spirit choose Greek for its language
The Holy Spirit inspired the writers to use the Greek for a reason. It’s nothing short of blasphemy to second guess the word choices of the Holy Spirit.