It's shitty when parents don't put their child first in situations like this, he sounds as if he is detached and un bonded with your child,
How hideous for you, nothing worse than your child being hurt by a parent,
You may have to accept he will never be the dad you wanted for you DC even in a little way,
she is playing power games, shrug the pair of them off, I would try to ignore them from now on, let him make the effort if he wants to,but don't waste anymore energy on them,
a normal person no matter what was going on for them would send their partner off to tend a child in its hour of need, she resents your child, if she feels the need to compete with it for attention, be careful with that one, she clearly didn't want a second hand man with baggage.
withdraw any unnecessary contact or communication, people like this feed of the energy, stop fuelling her.
good luck with the DC.