I think when you get the feeling to do something for them. Maybe you should help her figure out your LL. I always try to think of something that would have meaning to that person.
Just a real simple example: My boys love XBox games. I got them the one they have been salivating for, for their birthdays.(They are 3 days apart and both wanted it. They can play it together).
D11 is into this new fad of crazy bands or silly bandz (whatever they are called) so I just got her a package for the heck of it and surprised her. As long as it is from the heart, they will know.
I get the in-law thing too. My MIL and I had a falling out. I apologised, she didn't. My FIL I guess never told her I apologized. Really it ended up better that way as I didn't have to worry about all of their emotions too. They are reaching out to you during this difficult time. I would say it would be good to reach back.
hugs, kat
Me-53(and learning!) S24, S21, D18, D17 Just keep swimming, Just keep swimming. Dory