Almost 2-yr-old still on baby food!

[CrazyEight]

This is getting more and more ridiculous. I spoke to Mom, she seemed like she was on board with cutting out baby food, so that's what I've been doing. He eats NOTHING. Right now he is whining at the table looking at a plate of pasta, tomato sauce, and mixed veggies, all cut up for him. His baby food is literally the same thing, just mush (he eats those disgusting Heinz meal ones, like "alphabet pasta with tomato sauce," etc)
I thought we were on the same page, and then a couple days ago, dcmom suggested that since that day I would only have her kids and my own kids, that she take a day off (must be nice!) and we take the kids to an indoor playplace for a treat. We got them Mcdonalds afterwards, and he was eating a grilled cheese, one of the very few things he will actually eat. He had a couple bites, and then started whining, and the second he made a peep, she whips out a jar of baby food and starts feeding him! The whining probably wasn't even due to the grilled cheese, he continued to eat it! I couldn't believe it - where is the incentive to eat real food??
I refuse to give him baby food, so he refuses to eat. The problem is, he goes home and gets fed baby food and baby cereal every night for supper, so where is the incentive to try real food? He's simply going to starve himself all day with me, then go home and get filled up with mush.

I have to talk to mom again, but I don't want to offend her. I've tried already, and she claimed she was ok with it. Well, obviously not! Now I'm faced with him either screaming through nap because he's hungry or caving and giving him the damn baby food, further reinforcing that if he cries or whines long enough, we will all cave and he will get what he wants. If the parents won't cooperate, I don't see the point in my day suffering.