Returning to Cannes, Zaros and Lucios had already calmed down with Biacko's intervention, so they moved on to discuss more important matters. Zaros now calm, asked about what Biacko had said earlier.
Biacko had told them when they were about to launch themselves with all their strength against the enemies that Andrew and the others were fine. It must be understood that his grandchildren were with Andrew, so it was not a matter of just protecting Andrew.
Zaros like most powerful demigods, tends to distance himself from family and loved ones, but that does not mean that he does not love them, just that he shows a colder attitude.
This is a common characteristic of the powerful. Since they feel so close to divinity, they distance themselves from their mortal loved ones, but that does not mean that their feelings die.