WMG / O Human Star

Sulla already knows Al and Brendan were lovers.
One of the heaviest implications of Oh, Maker. She likely fully realizes that Al wasn't just her template, but her other dad.

O Human Star is a 'Parent Trap' Plot.
Brendan Pinsky's estate had commissioned Al's complete resurrection, but Brendan knew nothing of these plans. But Sulla did, and wants her two dads to have a second chance together. Sulla took Al's multitool from among Brendan's things (which is why Brendan couldn't find it), and arranged for it to be in Al's pocket when he woke up.
  • This would suggest that she thinks of Al as her "Human Star," since Brendan is clearly her Maker.

At this point, the evidence is clear. Al left his parents at an early age, and his parents and early childhood are never, ever a topic of discussion, even after Sulla has a dream about a childhood violent incident. Going a bit further, this makes the many differences between Al and Sulla more clear. Al was raised by parents were (at least) physically abusive, consequently he "acts in" by being withdrawn and slow to trust, while Sulla grew up with a dad as far away from that as possible — full of love and support — and she's much more outgoing.

All is going to invent coffee that synthetic beings can drink.
At some point he'll snap from frustration and barricade himself in a laboratory, ignoring all pleas to come out, until Brendan and Sulla finally find a way to open the door, and when the smoke clears, there Al will be, with a steaming mug of perfect coffee, safe for robots, cooling in his hands. Eureka.