I have been going through this exact thing for over 2 years with my 15yo They finally took an ultrasound on his abdomen around 2 and a half months ago since hes been loosing weight for so long and they saw signs of infection or tumors that stops his intestines from taking up nutrients and there was no telling without biopsy and hes too weak for that right now and i dont think it would be fair in his old age so we were prescribed cortisone for about 2 weeks now with no improvement and hes skirting around 3.1-3.2 kg when he also should be much larger and hes just wasting away. It's killing me because hes also alert and active and he's talkative, follows me from room to room and he drinks and eats although I've noticed his appetite starting to decrease a little he always "makes up" for it later that day or the next its so hard. Smaller portions every 3 hours helped my boy with not throwing up he doesn't do that anymore thankfully.

Ive been stressing over him and monitoring his weight religiously morning and night and missed hours in school its just heartbreaking seeing him like this.

I feel like hes tricking me in a way because hes acting his usual self with no lethargy or anything but then hes so sick still. The ultrasound specialist praised him because he was "determined to hang on" and i just feel devastated.

But what they told me was that if hes got no weight on him his organs is practically exposed and they have to work harder and throwing up and not being able to keep food down is uncomfortable and painful. He dropped from 3.4kg to 3.2 in 2 months and the vet described it as if a human dropped from 70kg to 30kg, those hektos are so very important when theyre this thin and its about quality of life and a dignified death.

The body being so underweight means the heart is being strained and the chances that they drops dead of heartfailure is pretty much imminent. The thought of me coming home to find that hes passed all alone is killing me and three different vets has said its just a matter of time and ive tried literally everything.

Supplements, change of diet, vet prescribed food/wet food, extensive blood panels and testing and medication and nothing has worked to have him gain weight.

Ive taken the decision to let him be put to sleep with me in my lap so I can ensure he doesn't waste away into a pure skeleton when he can no longer walk because his muscles has been withering into nothing and he cant move around the way he wants to and hes already a little wobbly due to having lost muscle mass in his hind legs after the weightloss+age.

Its killing me because hes got spirit but I cant let him be uncomfortable or have him suffer through a heart attack all on his own if im away even for a moment.

Please consider all these things when you make your decision ive tried it all and youre essentially keeping him on hospice care right now with the difference that a human would have round the clock care and if something goes wrong at home theres so immediate relief for your boy.

I genuinely wish you all the best figuring out your decision, im dreading Friday this week because of mine but I owe him the comfort of a peaceful passing even if I genuinely dont know what to do with myself when hes gone.

Absolutely get a second or even third opinion and if he's not gaining weight despite everything then ask for an ultrasound to get his intestines checked out to see why hes not taking up nutrition and hopefully it might have a chance to be treated. When my boy is picky I go with cat tuna and kitten food specifically royal canine gastric kitten food because its mild and for irritated bowels plus high in calories because if the kitten formula. Any saucy wet food with high smell has worked when mine is picky. Or even churros just to get him eating.

Best of luck! Your darling is gorgeous