Clearly their relationship deteriorated once BJ started his lecturing gig and Hollyhock found out about New Mexico (nail in the coffin being the televised interviews). However I can’t help that feel that Hollyhock has some of the same character flaws as BJ, and despite his major issues , he’s still family. In that sense maybe BJ would get her in a way others wouldn’t. I kind of hope that in the long run BJ gets his shit together and they can form a healthy relationship.
I could see Hollyhock going no-contact with Bojack for decades before finally breaking the seal and reaching out, only for Bojack to be found in deteriorating health (mirroring Beatrice). Hollyhock would finally understand what Bojack meant about not being able to get the closure he needed with his mom.