Most cockatiels are unfortunately... They only bond to one person/bird and once that bond is made everyone else kinda sucks in their heads. It took Spike about 6 months to allow Joey to pick her up when she crashes or not bite him when he tries to give her a kiss. But thats with him being around her every day
Feel free to message me any questions, I'll try to help the best I can!
Rummy- Mini Rex Rabbit
Diz jr- Betta
Yoshi- Crested Gecko