who knows "non-performing note" and "double closing"?

Come back for follow-up

One agent called me to buy the neighbor unit which got burned and storm demaged, and belongs to the bank. She says the neighbor unit  is a non-performing note. If I buy it, she will do double closing , with me and bank.

Is there anyone who has this kind of experience ? what do "non-performing note" and "double closing" mean?

I offered 15K, she prepared a contract in which she would like to get a commission of 5k. Is this reasonable?