I am sorry you feel this way but it is really a matter for the new parents and your DIL in particular. It always used to be traditional for the maternal mum to “move in “ to help the new mum out in the “lying in” period.
One month is a very short time, and if your DIL and her mum are close, it is perfectly natural. Don’t fall into the trap of competitive grandparenting, you are the one who will get hurt.
If the other granny is there at the weekend, how about inviting them all to Sunday lunch?
Otherwise you are just going to have to be patient and understanding.
I don’t agree that the new parents OR the other granny are being uncaring or unfeeling. 4 weeks is VERY early days.
BTW you must have a very short memory if you think your DIL and her mum are “out and about” or having” a relaxing time! “ With a 4 week old baby? I was lucky to be out of my dressing gown and into clothes by lunchtime!!
Smart Meters. Am I being over-charged?
Can I use my bus pass on London buses?