Is my MIL wrong or are we wrong? (Ruining our surprise for grandma)

So little back story I started dating my husband at 15 shorty after meeting his mother she asked what my parents do for a living I told her and she realized they make pretty good money. She then continues with comments like “I bet your parents are greedy with money because that’s how wealthy people are” . She constantly talks crap about people who make good/ or decent money (and my parents even though she has never met them) and says they are selfish or greedy. The funny thing is my parents are very generous and my MIL is the greediest person I know. My MIL doesn’t make a lot of money herself but gets large child support check from the fathers of all her children. But yet never buys clothes or anything my boyfriend needed. My boyfriend basically lives with his grandma who doesn’t have a lot of money and barely gets by, his grandma is one of the sweetest people I ever met. his mom is always off living with a new boyfriend after new boyfriend. My parents like my boyfriend and see how hard he works at 15 years old. So Christmas comes around and my parents take me out shopping to get gifts for everyone including my boyfriend I buy him a lot of clothes he desperately needed (he didn’t own a warm jacket in the winter, his shoes had holes and so did a lot of his clothes) and my parents buy him a brand new Xbox with some games. (I asked them to buy it for him because I knew he would love it and he has never gotten a expensive gift like that). So the gifts don’t go over well with his mom and she takes the Xbox away from him (I believe she sells it). From this day forward it’s pretty clear she doesn’t like me.

So fast forward 4 years me and my boyfriend have our own small place we don’t make a lot of money and I would definitely consider us “broke”. We don’t have much and barely can afford the things we need but we get by. My parents actually do help us quite a bit by buying groceries for us occasionally although my boyfriend hates when I ask them to because he doesn’t want them to think he can’t take care of things. His mom on the other hand expects him to take her out to fancy expensive restaurants we can’t afford because “that’s what sons are supposed to do for their mother”. She constantly complains to him if he buys me a gift and says he shouldn’t buy me anything and he should be buying her gifts.

So fast forward it’s our 7 year anniversary and we are going to Disneyland (my parents buy the tickets as a gift ) and we are paying for our hotel and travel expenses. He tells his mom about our trip because we are both very excited. Instead of being excited for us she drives over and yells and screams about how he never takes her anywhere like that and how selfish he is and completely put us in a upset mood the day before our trip.

Now it’s about to be our 11 year anniversary (of being together, 3 years married). We are much better off then we were and make decent money we actually moved in to his grandmas house to pay her bills because she was going to lose her home. She is like a mother to him way more of a mother then his own mother ever was. It is now kinda a tradition of ours to go to Disneyland for our anniversary. Of course his mom gets all snooty and pissed off like he should be taking her there. (the last thing we would want is to go with her, he hates his mom and has grown up to realize how terrible she actually is). Then his grandma says to us that she hopes one day she can go to Disneyland before her time is up. We talk about it and decide we are going to surprise his grandma and bring her with us on our anniversary trip. His grandma was so excited it was the cutest thing when we told her we got her a plane ticket and tickets to come on vacation with us. Well his mom finds out (his mom is the grandmas daughter) and comes over screaming and yelling and calls us selfish and makes the grandma feel terrible for coming with us. Is she wrong or are we wrong?