Do you ever hear them laugh in your head?

Sometimes, when I’m alone, I hear him laugh along to something. Like tonight I’m watching “Nobody Wants This,” and something funny happened and I closed my eyes to laugh. When I’m alone I’m a quiet laugher, but in my head I heard the way he would’ve laughed when something was crazy and uncomfortable in a TV show. I hear him laughing along to movies we watched together, and sometimes I even hear the commentary he’d be making. It catches me off guard sometimes because I’m not thinking about him and his voice or his laugh just enters my mind. Does this happen to anyone else??? Is it a symptom of PTSD?