Pushing back a payment arrangement?

My bf is on a payment arrangement that splits his bill into two for the month. Around 50 dollars each. His bill is due the first of the month and that’s the day we pay rent. I help out with the bill when I can as he pays the entire rent at our apartment. Will he be able to call and push it back a few days until he gets paid again?

I can make the payment but I’m budgeting my money on getting to work and food and other bills until I get paid again in 2 weeks. Just curious if he’s able to. He tells me he can’t cause of the arrangement. Thanks!