My comment - think about a couple of things here:

- where daughter is studying may have influence - that suggests she will be staying wherever it is for some time (given the 25,000 miles mentioned above from MEL, it sounds like it must be in europe or noerh america at a guess). She may wish to redeem while o/s, or at the very least travel around the area she is in, and thus some affiliation with a carrier in that region might make some sense (specially if she might do enough to reach a status level).

- I'd worry less about UA and US now, who are both out of Chapter 11 and doing OK.

- Think about how the miles might be spent in the future (this is tied in with the first point) - perhaps on her return to Australia - eg: an award to asia or the south pacific. Look up the redemption tables to see how much an award might cost to somewhere she might like (UA is good value with Star awards to NZ/South Pacific for 20k miles in Y, 30K in C).

KF may be a good option, but as I say it depends on the end goals. Also perhaps consider any partners (eg: credit cards, etc) she might use while studying and back here to earn additional mileage.

I hope she enjoys her studies