WWYD? Senior guinea pig with multiple health issues and possible reproductive complications

Hi everyone,
I’m hoping to get some opinions from people who have experience with senior guinea pigs or reproductive disease.

My guinea pig is almost 5 years old, and it’s been a difficult year medically.

She originally weighed close to 800g before being diagnosed with coccidia. She went through two rounds of treatment, but unfortunately the medication took quite a toll on her gut health, appetite, and weight. While the parasite count in her stool was significantly reduced, it wasn’t completely eliminated. After discussing it with our vet and seeing how much the treatment was affecting her, we decided not to put her through another round because she just wasn’t coping well. Since then, she’s never regained her previous weight and has been hovering around 600–640g.

Later, she developed a head tilt. Our vet suspected E. cuniculi (although we didn’t do the confirmatory testing because it was expensive and would have taken time), so we treated her based on the clinical signs. Thankfully she improved and adapted well, but not long after that she started developing progressive hair loss.

Recently she stopped eating properly, developed mushy diarrhoea, and I’ve been syringe feeding Critical Care. She’ll still nibble on small amounts of food here and there and is still interacting with me, but she’s definitely weaker and more tired.
At her latest appointment, the vet performed blood tests and said that, overall, her bloodwork looked fairly good for a guinea pig of almost 5 years old. During the examination, they also found an abnormality in her reproductive system and think her hair loss may actually have been related to a hormonal or reproductive issue all along. They’ve recommended seeing an exotics specialist for a more detailed ultrasound.

The difficulty I’m facing is the cost. Her recent consultation, blood tests, X-rays and diagnostics were already close to S$500. The specialist consultation and ultrasound are estimated to be another S$600, and if surgery is needed, I have no idea what the final bill would be. (Prices in SGD)

I’m trying to make the decision that’s best for her rather than simply pursuing every possible treatment.

For those who’ve been through something similar:
Would you see the specialist before deciding anything else?

Have you had an older guinea pig undergo reproductive surgery? How did they do?
Given her medical history, would you still pursue surgery if it turns out to be an operable condition?
At what point would you feel that euthanasia is the kinder option?

I know nobody can make this decision for me, but I’d really appreciate hearing your experiences and how you approached similar situations. I love her very much, and I want whatever choice I make to be in her best interests.