<human>: so recently my roommate and i went to china for the month. we had a fantastic time! for one of the weeks we met up with a couple he knew from work back home and toured Beijing a bit together. we all had a great time and it was totally fine. the day we were supposed to ship out we had to get a taxi to the train station and because there was more than 5 people we had to take two taxis. unfortunately the wife of the couple didn't want to carry much or be responsible for anything really (she wouldn't ever have money on her or hold anything important except for her camera), anyway we were all flustered trying to make sure we ended up at the right place that i ended up holding a small backpack for the husband. i didnt really know what was in it, i mostly thought it was random things like toiletries (no bathrooms have tissues etc in china usually) so i just placed it in the trunk with my bag. except it was a really small bag that was completely black, so when we got out of the taxi i totally didn't  even remember i had it and left it in the taxi. no big, except it had his passports and cameras and iPad minis. so not only did they lose that but they were supposed to fly out the next day, which they couldn't without passports etc. so they spent an extras few weeks srting it out and it cost them thousands to fix and repolace. 
now hes asking that i "donate" what i can to help out. how much should i be responsible for?
I'm not particularly close to them but we have some close mutual friends and i already get the vibe that i'm looked at negatively now that Ive returned for losing the bag. i don't really have the money to completely reimburse them without taking out a loan though. so some advice would be good.
thanks for your time

Can you succinctly summarize the text in 1-3 sentences?
<bot>: friend handed me his bag with his passport in china. i didn't realize it had his passport and misplaced it. he is asking for donations. how much am i responsible for?