Please resolve a dispute if you can possibly:
Friend A: Is splitting up long term dp amicable so far and wants to meet up with friend B alot. They usually meet 4-6 times a year. Solid old friendship. Friend B is married and lives 2 hours away and works. Friend A also works ft both busy with dc but is now free every weekend and would like to see Friend B more often.
Friend B: Clears the diary and Friend A decides to come at the weekend and both tell kids all excited and good.
Friend B: Buys in tons of food, cleans house top to bottom, buys Friend A flowers all checking with Friend A day before all is still good.
Friend A: Texts Friend B later day before to say ex dp's df is coming back to UK as his great aunt is ill.
Friend A then decides to wake up dc in the middle of the night and take them to airport at 2am to collect him, and then to stay up with FIL in to 4am. She then drives FIL to London for FIL to see dying great aunt ( 5 hour round trip). Friend A has met her FIL all of 3 times in 25 years as he lives in Australia. Zero relationship. FIL could have got a taxi or hotel or any number of things he is a fit and wealthy man. Meanwhile ex dp is in Prague apparently 'working' 
Friend B finds out 2 hours before Friend A is due after cooking all morning that friend A is not coming, she is in London now sightseeing and shopping whilst FIL is seeing Great Aunt.
Friend B seems to feel very hurt that she has spent two days preparing special lunch and dinner for Friend A, and Friend A has decided to cancel at the last minute for someone she never sees, and isn't likely to in the future....she felt very hurt Friend A seems entirely indifferent to cancelling last minute with almost no notice (this would not so bad but Friend A unfortunately has had to do this at least four times in the last few months)
Friend A has had enough and can't be bothered anymore, is she wrong or should she be more understanding?