Squeak is 12 years old & had the snip. Generally he is overweight/big cat but over the last 4-6 months he keeps being sick, it's mainly bile & foamy, sometimes his food in it but we think there is blood in it too as it's very red and we don't think it's his food. He has lost 1.2kgs which is obviously a lot of weight.
We have spent £400 at Vets, who ran blood tests which have come back normal, did an x-ray and ultrasound and they cannot find anything. We thought when we took him in that morning that they would carry out an endoscopy but as they didn't see him to really late that day and it would have meant an anaesthetic and they didn't carry it out. They have said we can go back for that but my husband really is against it as he wasn't right when we got him back after being sedated, it really affected him so we are worried about putting him through an anaesthetic only for them to find nothing again.
Then very recently he has started spraying, peeing and pooing in the house, he has never done this before unless it's pouring with rain and we know the signs and chuck him outside. Yesterday, he was sick, followed by a spray then a poo

I do find if I feed him small and often it helps a bit, we did try him on Omeprazole to see if it was too much acid in his stomach, we thought that was working as he wasn't sick for nearly two weeks but it's started again.
I know it's very hard to determine what the problem is with cats being sick but any advice would be welcome.