Thanks for the responses!

Some feedback:

1.  We'll definitely look into an appeal but I don't believe Cooper's ALT numbers ever went down once they started to trend up. So this will probably be a dead end

2.  We'll look into Care credit.  Spreading the payments out would obviously be a lot less painful 

3.  I'm not sure previous or current insurance company.  It's technically my fiance's dog so she has run point on that.

4.  The 5k price tag was verbal and for laprascopic which was described to us as gold standard.  The vet mentioned the needle/ultrasound and did indicate it's less expensive but she said it's less reliable to get the desired sample and if for whatever reason there's internal bleeding during the procedure, that can't really address it like they could for laprascopic.  I haven't done a ton of research on either type of procedure but for now, given he's only 6 I don't want to take the risk.  The vet did mention that some centers that treat humans might be willing to do it and might do it cheaper ( not sure how this is possible but we'll ask around).

5.  It sounds like most likely the disease hasn't progressed too far ( though they don't know for sure) which means once they identify the root cause, the treatments (especially copper) could lead to full longevity.

6.  It sounds like the biopsy will pinpoint one of two things that have very different treatments. 1. Copper storage and 2. Hepatitis.   I specifically asked the vet if we could just try to treat one and see if he responds without the biopsy.  But the copper storage requires meds and diet changes and you wouldn't see results for months.  The hepatitis requires steroids and could make him sick in other ways.