Hi @Cassandra
It is not clear to me on what grounds your partner already received residency in Germany. It is correct that if an EU citizen works in Germany, their family members have the right of residence also. This is why your child has the right to be here.
The partner of an EU citizen can also receive residency but only if they can prove they are in a long-term relationship (generally at least two years). Here is more information on this:
https://***-eu--gleichbehandlungsstelle-de.translate.goog/eugs-de/experten/newsletter/aufenthaltsrecht-fuer-eu-buergern-nahestehende-personen-1940828?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wapp
Therefore, I do not know on what grounds the father received a permit. However, he can continue to have a residence permit after moving out. His permit will not be based on you but on the basis of his relationship with the child. He needs to prove that he has contact with the child, is involved in the childcare and since he is working, is providing financial support.
The question of residence permits for non-EU parents of EU children is a complicated one. There is much confusion among the authorities and advisory services about in what cases it is possible. I encourage you to check any information you receive on this.
Best,
Éanna