One of the qualifications of being an elder is “able to teach.” Often this gets interpreted as “able to preach.” Which is not the case. Here is a great definition from Thabiti Anyabwile in Finding Faithful Elders and Deacons on what this qualification means:
This ability is not limited to public teaching from the pulpit. Men with this ability might be gifted public teachers, or they might simply be gifted for one-on-one or small-group settings. Some men are not exceptional public speakers, but they are teaching and counseling the people around them from the Scriptures all the times. Such men should not be disqualified from the office of elder.