In queensland you can get learners 1year after you get your provisional car license. doesnt matter how long you have your learners to go for RE (provisional) is compitency based. So if you can do all the compitency's figure 8's, slow ride 10metres etc etc you can get RE. Once you have had re for 1year you get open bike license
L's and RE is limited to - LAMS bikes (learner approved motorbikes) basically its =<250cc bikes and some 650 bikes. Just make sure they have the lams stamp.
O's Unlimited CC's.
Being competency based take it into considering when training i did it with a grp called pro riders at rocklea (pro honda during the week) These guys will get you re license in two weeks at $270 a lesson starts at 6.30 in the morning concludes about 3 in the arvo. And the cost caps at $600. 90% of the class had only riden on farms or not at all prior to those two lessons. I walked away with my license 2nd day.
As for bikes get a 250 or less i think the rules have varied based upon your own body weight. But double check that. Im about 90kgs and on my 250 hyosung it doesnt soar out of 1st-2nd but once im cruising its great.
Just be aware...your now the smallest vehicle on the road. Small obstructions hell even painted words on the road can be a hazard. Being new to the road im hesitant to commute to work but saturdays past 3 weeks i make it my goal. 1st saturday a lady almost hit me. 2nd saturday i fish tailed right before a turn i got off to go look at the road and there was like a sheet of laminated plastic on the road. 3rd saturday All good
got home in record time "didnt speed".
As for gear its really all the same the only variance being price tag. The one thing i didn't pay cheap for was my helmet. You have to do a lot of shoulder checks and you want to be comfortable.
Helmet $900
Jacket $350 (not wet weather)
Gloves $20
Pants $100
Hyosung 250gtr $3000 (3000km's on the clock 2006)
happy to send you my excel spreadsheet on all the lams bikes i checked out. Just fyi i ruled out ninja 250 on the mere fact its super popular(im not a conformer) and didnt have digital display. Hyosungs arent very reliable past 10,000kms
If he does decide to upgrade to a larger more powerful bike try and talk him into something smaller like a 600cc rather than a 1000cc, theyre both incredibly quick but a 1000cc is very easy to make a mistake, going full throttle in 1st 2nd or 3rd in mine will lift the front wheel off the ground and its a 11 year old bike, newer ones have a little more power. As long as your son is sensible he will be fine, definitely suggest some advanced riding courses (Almost a track day in a sense) though 
