I don’t mean we speak in notes—we’re not twin savants or anything like that—but we use guitars the way fathers and sons use baseball
This makes the authors story more human. Him and his brother used music less as a way of speaking and more of a way of bonding. The author also mentions a 7 year age gap his brother and him have and how they started to bond after his brother discovered him playing music later in the essay. This reinforces the way music connects the brothers, it acts less of a form of entertainment and more of a natural force that binds them.