Aside from the fireworks has anything changed recently? Have you noticed any other odd behavior along with what you already mentioned but perhaps wrote it off as something else? Also when he does it is he fixated on anything in particular or will he do it just looking in a general area but still acknowledging his surroundings?
"It takes courage to grow up and become who you really are" - Cummings
"If think you can't, you're right. If think you can, you're right." - Hatton