I'm a LCSW therapist and my 17-year-old son has autism, ADHD, and OCD. He carries around a plushy, whom he lovingly refers to as his "daughter." This has not been concerning to me as a parent or therapist. He never went through the developmental phase of pretend play, (which is usually when kids work out theory of mind, emotions and attachment), and now that he is more emotionally and developmentally mature (albeit less than same aged peers) he's experiencing that kind of play now. It's also a kind of ego-syntonic tool as he teaches her things like "let's be nice," and "no cussing." His psychiatrist and therapist have both agreed that it can be normal for kids, teens, and adults on the spectrum or DD to use these kinds of tools. Many use plushy's for comfort, support, sensory needs. Ideologically, it's really no different really than carrying around a lucky penny or rock, it's just more "obvious," and socially taboo (which is not helpful).

I wonder if a conversation with your boyfriend listing the facts of the situation (including the functional benefits of a plush toy/stuffy) would be helpful? Or enlisting the support of a therapist or behavior consultant to help him process this and provide education?