Dear @Timtime,
Welcome to the Wefugees Community and thank you for reaching out to us.
I assume your friend was not registered as refugee but was granted "temporary protection" in Germany, right? This usually applies to the people who fled Ukraine after February 24th 2022 and who do not have to apply for asylum in order to get a residence permit in Germany as well as in other EU countries. You may find more information on this at an official German authorities' website here.
As far as I know (and as I also read on this trustworthy website - in German though), Ukrainians who were granted this temporary protection status in another EU country and who subsequently come to Germany can still receive a residence permit here. Be aware that the initial residence permit in the first country may expire.
I am not familiar with the procedures in the Netherlands. However, since all EU countries found their policies on the EU "Temporary Protection Directive", rules and regulations should be quite similar and harmonised in regard to this matter. Therefore, I believe it should be possible to get a residence permit in the Netherlands after moving from Germany.
You can find information on the reception/registration of Ukrainian refugees in the Netherlands here and also here (both official government sources). Before eventually moving, I would recommend your friend to get some counselling from Dutch experts as well. You may contact this organisation (VluchtelingenWerk Nederland) for advice and detailed information, for instance.
I hope this helps and please don't hesitate to get back to us with any further questions.
All the best,
Meike