If he starts open mouthed breathing and you notice a change in color of his tongue and gums to blue instead of pink, that is a definite sign of respiratory distress.

As long as he is eating, drinking, and somewhat comfortable he should be stable.

The problem with cats and respiratory distress is that it can come on quickly.

If he loses his appetite or begins open-mouthed breathing you will have to make a decision to have him put to sleep to avoid any further suffering.

I'm sorry that you are in this position, it is a very difficult one. Keep him comfortable and spend as much time as possible with him.

Let me know if I can be of further assistance.

Hello Oliver:

I'm sorry to hear that he is having trouble. Keep him as quiet as possible throughout the night. Keep his food/water dishes and litterbox nearby so he doesn't have to spend much energy/oxygen by moving around.

There is a resuscitation acupuncture point located on the nose in the vertical line of the hairless part of the nose beneath the nostrils if he begins struggling to breathe. You can use your fingernail or the tip of a pen to stimulate the area. This may help keep him comfortable in case you do need to take him in.

Hang in there, I know it will be a long night.