Haha sorry, but this makes me laugh, this exact thing happened to me and it freaked my husband out so bad. I think I had my baby about a week later, but my husband is still tortured by this memory.
Your cervix drops as your body prepares for labour, if your baby is starting to engage then its head is dropping down. You go from 5/5ths as is they can feel the whole head down the way to 0/5ths palpable meaning that the head is fully engaged in your pelvis and cannot be felt above it. You have a little way to drop yet (that might not happen until you are actually i labour so do t panic) but its more likely that your man is feelimg your cervix than the baby's head (its not impossible that he is, but I think the cervix is a more likely possibility when baby is not fully engaged yet :)