Mine (healthy male dragon) brumated the first time at an age of 9 months. Now, a year later, he is brumating for the second time.
Brumation can last from just a few days to three months. My dragon did almost three months.
I am only handling my dragon when he approaches me. Any caves, hides... are "no no" for me, means I never touch him in there or pull him out (emergencies would be a different thing, of course). When he retreats, this is his thing. When he sits at an elevated spot, looks at me, eyes following me: I put my hands in, close to him, and if he climbs up, I take him out.
So this means, when my dragon brumated last year for three months, I never touched him or took him out. I can see him in his cave, I can see he looks fine (not looking thinner, no
black beard).
This time, it will be the same.
Regarding feeding: As my dragon is not leaving his cave, I don't put in insects anymore. Live plants are always available as they are just planted into the tank. In case he wants to eat something, he could come out and eat those plants. (I know that he likes eating them, as he does regularly when he is not brumating. About half of the veggies/plants he is eating come from these live plants.) As soon as I would see him doing this regularly, I would put the insects back in (that's what I did when he ended his first brumation).
Yes. And we are also on the Southern hemisphere (Chile), our season is fall now.