Birds, in all honesty, fuck knows. I'm not going to say she's a bad mother, because mostly she's not. But she refuses to sort access out legally, so it's all by mutual agreement. Mostly this works, but every now and again (roughly every 6 weeks since they split, but the pattern isn't that clear, and depends on who she's been speaking to/shagging recently) she'll make an irrational/impossible demand, and when DS can't fulfill it (because he's working, his hours are irregular, zero hours minimum wage contract) her first response, every single time, is "You'll never see him again". Mostly she thaws within a day or two, though at one point she said if he went to a lawyer he'd never see his Ds again. The next time, it was, "See a lawyer, because you'll never see him again otherwise" so he saw a lawyer, and a letter was sent, and she's been Ok since.
But it was made very clear to my DS that if he went to court to have the 50/50 thing set down, he'd probably be reduced to "every other weekend, and one evening a week" and that is so much less than he has now he's not willing to risk it.
She gets the CB, so she is the RP, even though the dc spends more time with his dad than with his mum. So she gets to call the shots.
Not all NRP dads are deadbeats.