Advice needed - food related

We have a 6 year old Siamese female cat that has been diagnosed with a cancerous tumor in her eye.  Surgery is questionable because of this girl's skittish behavior when out of the home.  She doesn't settle well and can be very easily spooked.  I don't think she would tolerate nor do very well in a surgical / vet setting.

She has not been eating well at all and has IBS.  She and her house mate both have IBS (both rescue cats)  They are both on Iams Low Residue dry cat food.  This little girl is not eating well at all and has dropped weight.

Is there a wet food that is close to the Iams Low Residue that I can purchase at Petco or Petsmart to help her to maintain her weight until she tells us it is "time" to let her go?

I don't need comments about surgery, just food.

Thanks in advance!

Actually I think any of the high quality foods with very few additives, as close as possible to just meat, liver and supplements would work.  They are naturally 'low residue' because of the lack of fillers.

Nature's Variety Instinct LTD

EVO

Wellness CORE 

Those are 3 that I can think of but I am sure there are others.

Thank you.

I did get one small can of a salmon/tuna that was grain free and so far it seems she is tolerating it ok.

I am just trying to keep her happy and comfortable for however long we have left with her at this point.  She still plays, purrs, wants attention and seems comfortable.  But is just having issues with the dry food now.  I think the crunching is causing pain?

Thanks for the advise