Emm14 - this weekend is your chance to build a relationship with your DIL. Firstly, regardless of the fact that your son has invited you to offer support, he would not have done that without DIL's agreement, so you need to bear in mind that she wants you there and clearly because she sees some value in that. Secondly, whilst you don't say whether the DIL's mum has been ill for a while, it may have been that the death was expected and your DIL may have suffered with lots of emotional turmoil over the past year that has worked its way through to her interaction with you. So this is the opportunity for you to show your DIL your worth and I would suggest that you do this by openly acknowledging her grief and offering what you can. Practical advice - look around the house for photos of her mum, if you see any, make positive comments 'what a lovely photo of your mum' and if there are no obvious reminders suggest some 'have you thought about having that nice photo of your mum on the sideboard, etc., etc., - you could ask her permission to go and take flowers to the grave if there is one, or suggest that you buy a small plant or tree to put in their garden as a remembrance and something that a story could be told about to your grandchild to keep the memory alive. If you give your DIL the impression that you know how difficult it is for her to lose her mum, and that you think it's important for her memory to be kept alive through continuing bonds - with photos, graveside, plants, bench, etc., your DIL will find it hard to be rude to you. Let her grief work its way through and I'm sure she will realise that she still has a MIL in you and want to make a good relationship out of that.