How she should handle it ?
Such things are always hard because it's about hope and expectations. I got rejected a lot in the beginning. At a later point in my "career" I was rejected by a company I wanted to work for after being in the final round.
The CEO actually recommended me to another company, which was nice. My GF got into the company that rejected me and now I got information how it works on the inside and I have to be honest .... less magical. I worked with them they weren't superior they just needed a different skill-set :).
But still at the time I was left with the question why they did not want me. which sucked and stuck with me for a while. It passes and as long as she doesn't take it to personal she will grow on it.
I was in a multitude of companies and had a lot of interviews I got invitations from google, amazon and others never took them, I don't like big corporate. And still I will probably get rejected a lot by even small unskilled companies because I don't fit in their profile.
So rejection will always happen and if she takes her time, wait a little for the emotions to settle and reflect on it afterwards she can benefit from it.
to put one of my favourite mantras, i learned. in place "people who do a lot will make a lot of mistakes, people who do less will make less mistakes, people who make no mistakes are doing it wrong."
She has a learning and growing opportunity now and she should take it.