C.P.
I grew up with a grandma like this one (my step-dad's mother)from the time I was two and she treated me exactly the same way. Even at Christmas time she would get something for all the other cousins ($100 gift certificates) and maybe give me a $10 bill if she remembered. It was very hurtful for me to have to spend time around her and I dreaded every holiday. Luckily I had a great step-dad who treats me like his own daughter and I never wanted for anything. He tried again and again to explain to her how I felt but she never was able to see me as "real" family. It will only get worse as your children get older and realize what is going on, if your husband speaking to her hasn't helped the situation then I would ask her to stop buying gifts and/or refuse when she buys gifts or treats for your one son. Once I was old enough, I made the decision to stop seeing her and attending family functions for that side of the family. I now have little to no contact with that part of my family and I would hate to see that happen with yours.