It should be noted that beyond the severe physical penalties associated with a familiars death (-1 permanent loss of Con, death if you fail a system shock check) that Kayess has been close friend and companion to Lughaidh for over a decade.
As such Lughaidh does not view nor use her as a mindless summon or attack dog, the cases where he has done so were in extreme cases where to do otherwise would result in certain death of himself, or a ally. In total to date he has done so only 3 times.
The two together are a boastful, mischievous and happy go lucky pair that will take on all comers, within reason.
If a choice between Kayess or a party member came up, he would pick Kayess and vice versa. This is simply the nature of the pair.
Much of this would likely be easily observed by seeing the two together around camp, rarely are they apart, or asking of them.
Besides that kayess will willingly participate in campaigns of liberation, providing of course the object being liberated is fruit. She often takes joy in pulling small pranks via her ability to cast cantrip and go invisible at will. Her euphoric breath is something she tends to rarely display except as a final resort.