Doing that in a year or even six months is plausible, depending on how lucky his circumstances are, but three months strikes me as a bit of a stretch. At $10/hr * 40 hr/week * 12 week = $4800, ignoring rent, food, incidentals, and taxes.
If that were to become an obstacle, one solution may be to get a second job.
And yet the OP writes that he's having trouble getting even one of these jobs. It may be hard to believe, but some small towns have a vast, vast excess of people wanting these jobs.
I could also suggest he goes off to western north dakota to work in the oil field, but I don't know if that's such a great idea. I have some friends that have done that. It sounds horrible, and they look like they are about 15 years older than they actually are. Plus you need the money to get there, and need a car, all of which is probably $5K+ anyway.
How in the world could anyone save $5,000 in a summer when they're not even pulling in that amount?
EDIT: Even working 80 per week only brings in $7,680. Factor in bills and you're still not hitting 5k, guy.
Edit: What bills does he have? Food is free, because you work in food service. Rent in a place like Yakima is < $400/m. Summer starts in May. Also, after 40 hours a week you get overtime.
I've never heard of a food server job that hired fulltime workers or allowed those reaching 40 hours to go beyond that.
I'm a developer today, and do ok by industry standards (not great, just okay, for now). However, I grew up in a less than trailer trash home, my dad was a janitor, my mom was nuts (I used to watch her talk to invisible people in a roach infested kitchen), my siblings were sucked into the poverty mindset. I was born with a serious medical condition. I've had some other crap go down that I'll barely tell my close friends, let alone an Internet of strangers, but trust me when I said I've had to rebuild areas of my life more than once. So what. I won't tell I have it all figured out, but I will tell you I will not be defeated. And I have little sympathy for those who tell me the horrible hand they've been dealt.
I realize that we live in a world where only the kids of the rich get to succeed, and the only way to start up your own business is to join an incubator. If you believe that, then you will be taken advantage of. Either push to be successful, or be the kind of person that the successful use to get there. They're more than happy to take your money and your spirit.
By moving to a lower cost area than Australia you still get a little of the "awesome, I'm traveling!" thing with low enough costs that you can try to do work that is relevant to your ultimate goal of getting a career in technology.
Stay in the U.S. and try to keep in touch with the comunity.
Also, if he finds Yakima "hell", being very close to tech centers, how can you expect him to adjust to somewhere that's REALLY in the middle of nowhere in tech terms - and, while you might think it's easy not to get sucked into local wages, he's unable to make US wages living in the US. In my country, a US McDonalds wage (8 dollars an hour) is much higher than most midlevel manager positions, and higher than standard developer wages.
If you're lucky and social, you can find your way onto a fishing boat; deckhands will usually get a percentage of the catch ($$$), and the work is easier.
I've been through Yakima a time or two before. A gritty wind blew continually -- it seemed like the kind of place where not even the dust wanted to settle. My sympathies to the poster.
I suggest to find some freelance programming jobs online. He could make some money writing articles about the stock market for SeekingAlpha.com.
In terms of education, I think he should do some courses with Coursera or one of the other free online institutions.
Also getting a rental unit without previous references from Australian landlords/agents is particularly difficult.
Be prepared to spend out a lot of $$$ getting set up.
Yes you'd be looking to pay that for a nice, new or renovated single bed apartment in the middle of the city or an expensive area. As hinted at though, as someone with $5-10k in the bank coming here to be a barista there's no way you'd be able to get a lease for one of them anyway.
Head even a 20 minute tram ride out from the city, however, and suddenly you can pay AU$1,400/mth for a 1 or 2 bedroom place in an older building. (Though you may struggle to get a lease anyway...)
If you were on a working holiday you would likely be better off finding a shared place with some like-minded souls, and end up somewhere around $1,000 for rent + all your bills and such to live somewhere pretty nice.
These figures sound good compared to US min. wages, but given the (substantially) increased cost of living I'm not sure this is good advice.
I do second the concern that Australia is expensive though. But there's no language barrier, work around and lots to see.
I spent 9 months in OZ, most of the time in northern Queensland working at a lime/lychee farm and some time at a banana farm. Since you are not in OZ yet, I doubt you will have any luck with gumtree/craigslist. Even if you are there it's pretty hard to get the job that way - the farmers really like to make sure you WANT to work and can physically do the work (at least I didn't manage to find work via gumtree).
The thing you have to do is go to the farms directly and talk to the owners/recruiters face-to-face. We bought a cheap 2500$ car between 3 people from Sydney and started driving north along the coast. There's quite a bit of work in the tropical areas during the summer months - bananas, mangoes, limes, lychees, avocados in late summer etc.
So my advice would be - get a cheap car, travel and work at the same time! (some farms hire only for the harvest period which for some produce isn't very long!)
Hope this helps a bit