Not bullying Lillie and I had read the thread, well most of it and it should be obvious that I realis it was your MIL and am perhaps justified in assuming your BIL is her son?
So that is that sorted I hope.
Nobody is talking about whether or not a person deserves their current financial position, but as a parent I would reserve the right to be aware that my offspring's needs might be different. As indeed ours have been at different stages in their lives. Again, I hope that is sorted.
You however express irritation that your MIL, who must be an excellent age - good for her- still lets you (with the aforementioned income) pay for holidays and meals.
There are many here (me included) who would not be surprised at that.
As a parent, the urge to provide for one's children remains strong, and I have been known to find it hard to accept graciously when my DD and SIL whose income has at least one digit more than our pensions, offer to foot the bill for a meal out.