Despite how nonchalant Cane was, there was no way he didn't know how Ethan's feeling toward Aliana, it was crystal clear for anyone to see.
And for the reason why Iris took Ethan inside the bedroom, it was very easy to guess, she must want the gamma to feel the movement of the baby, since she was very excited to have this experience. After her little bump, the movement of the baby must have solidified her status as a new mother, to really feel the new life inside of you grew was a happiness that one couldn't describe into words.
Even though Cane was not really thrilled with the image of his mate was being touched by another man, but it was only his possessiveness that was talking, it was completely absurd to think the two of them would step out of the line.
Ethan was a brother figure that Iris didn't have and it was safe to say the gamma saw her the same. It was also Ethan, who treated Iris nicely in the early day she became the luna of the pack.