Keep the lights and heat on , he'll then be able to bask when he wants too.
I've nudged the photoperiod down since April to 14 hrs and wont be going down more .
My water skinks are wide awake and don't seem to care it's winter now , eating me out of house and home , as are my two old bluetongues ( who are a bit more dozy but still very interested in everything and make fast work of their food ).
Both my yearlings are still basking everyday ( but spending more time , usually all afternoon , napping now ) , no reduction in appetites. Pooing as per normal for mine.
I think it's best to try to keep a yearling bearded dragon out of full on brumation in it's first winter .
My two juveniles (yearlings) have been turning their noses up at the greens and vegs too, so I just give these in disguise by feeding the crickets and superworms the greens and vegs I'd like the dragons to eat, and the dragons are none the wiser.
So I give my dragons crickets, supers ( as treats ) and bsfl . Having a holiday from raising silkworms for a while , will get back into them by hatching some of eggs likely in September when the mulberry trees are leafy again ( if covid19 has been eradicated in Sydney by them - very unlikely IMO) . The eggs will remain viable for a few years in ziplock bags in the fridge , and I want to concerve my remaining packets of chow powder , as it might be hard to get in Australia for a while til international shipping returns to better levels ( I suspect the chow sold commercially originates in China or maybe in India ).