Can someone advise please re bonded pair fighting

Hiya, I have a friend who has 2 buns, they are siblings, a boy and a girl. They are around 1 yr old. Originally thought to be 2 girls however boy is now neutered and no babies. This was a while ago and the girly is def not pregnant. However she has been building nests so is maybe a bit hormonal (she's not speyed).
The boy, Sprite, despite being neutered, seems to be bullying the girl, Drooper, to the extent she's scared to be near him so my friend has had to seperate them. Drooper was becoming very withdrawn and scared of my friend but now the buns are seperated Drooper has come out of herself and is back to normal again.
Any suggestions as to what she can do, will they ever be friends again? Would getting Drooper speyed make a difference even though Sprite is neutered. My friend does know about the health benefits etc...
Look forward to passing your suggestions on. Thank you

Getting dropper speyed would be beneificial as this would take away the hormones that may cause problems after she has had this done she can attempt to re-bond them XX

I think it will help address some of the hormonal issues if the girlie is spayed. Although now they are seperated their bond may already have broken down so it will be a case of starting from scratch. The girlie will need time to get over the op' before being subjected to the potential rough and tumble of re-bonding. Even if the re-bonding does not work out the girlie bun will benefit healthwise from being spayed.
Janex