Next Steps Advice on out Cat Suffering from Haws Syndrome

Looking for "next steps" advice on our cats condition...we trust our vet, but need some guidance on what to do next as we are concerned.

- He was diagnosed with Haws Syndrome on Friday and has the classic eye issues associated with it (i.e. inner eyelid showing, clear drainage etc.).

- His overall condition now is reduced appetite, lethargy and grumpy (i.e. does not want to be picked up or messed with) - all VERY unusual for him as he is food-oriented normally and has good energy and attitude.

- This has been going on for about five days

- He and our other cat suffered from a bout diarrhea a few weeks ago, stool on both cats is fine looking as of now. The house mate was worm tested and nothing was in the stool however he was not.

- He is peeing and pooping but less most likely due to the lethargy and reduced food intake.

- He is eating and drinking, but less

What have we done so far:

- Bloodwork - showed nothing abnormal

- No mouth sores/teeth issues

- No fever and all other vitals normal

- No conjunctivitis (no eye redness etc.)

The doctor recommended an appetite booster (Mirtazapine - we have not tried it yet) and "wait and see" approach given the Haws theory. However, they are also recommending an ultrasound (which we plan to do as soon as possible this week)

We also are going to get a fecal test on him as well, just to be safe.

Any other tests, experiences or "next step" options anyone can share???

We are just trying to move in a direction that makes sense and ensure we are doing all we can do!