I am sorry that your W was on an epic spewfest yesterday. That type of spew leads me to suspect that FIL probably "talked" nasty to her about you and how ungrateful you all were to W. Then W most likely turned to you and turned on the spew works.
It is so hard not to take this personally. You have to remember that W isn't rational at all and it's no use arguing back or trying to rationalize with irrational. Try to keep your responses short like "I am sorry you feel this way", "I can imagine how you would feel this way", "Thank you for sharing."
Next time, I would suggest that you cut this type of phone convo short because you have to be somewhere in 10 minutes. This is a good technique to nip the spewfest in the bud...so to speak.
