She should get invited to interview. 80% of applicants do. But, the university is currently so under strain with admissions that they're increasing the proportion of people who aren't invited.
Her work will be cut out for her when she comes up for interview! I got into Oxford by reapplying, having been turned down for PPE in my first year. I performed quite well at interview, but not well enough to compensate for my lack of a Maths A-Level. So having the right A-Levels is important. Having said that, lots of candidates without Maths A-Level did get in - they just had to give a virtuoso performance in both the exam and interview admission stages.
So - she should be well prepared for interview. I know someone at Oxford who went on a no-win no-fee interview training day paid for by his school for around £200 and he couldn't recommend it highly enough, though I don't know what you think about the ethics of that! Also she should make sure the written work she sends up is of the highest standard possible. If she can, she should write the pieces specially - good written work can make the interview a foregone conclusion, but so can bad. Also she should consider applying post A-level, when she (hopefully) has a solid set of excellent results behind her, and the added confidence a year out gives you. It worked for me.
Law is well competitive, but because few people study it at A-Level, much depends on the interview. So she should be encouraged...use this to her advantage.