Sleep regression

I know there's a 2 year sleep regression, my son has been waking up every night for the past month between 2-5 am asking for milk. Is that considered a sleep regression or could he be wanting milk at night bc he doesn't eat well throughout the day? He's such a picky eater and he has a sensory issue, I can't get him to try new things but he's also tired of the same things so he's complicated. I used to let him cry it out but now he gets off the bed and bangs on the door and cries non stop until I get up and give him milk.