We have always tried to treat our two DSs fairly and even handedly, according to their needs and what we can afford. In both cases, the in laws are fairly comfortably off and help out too. I believe that DS2s in laws treat him and his wife equally as a unit when it comes to helping out financially and also in terms of bequests. However DS1s in laws tend to exclude him from any financial arrangements, which they have in the past specified as being for his wife, their DD.
All that is their business, of course. Our dilemma is that we want to leave our estate to the GCs to help them on their way as young adults (we're hoping to reach the 'average age' for nowadays). However DS1 has 1 child and DS2 has 2, which would make for an unequal share out between the families.
No doubt it will be sorted one way or another, but it's rather a knotty one for us right now. Hopefully there's plenty of time to resolve it.....
Has anyone else had this issue come up, I wonder?