I concur with Bigcat. I sold an ‘07 Avy at the end of 2016 for $37,500. It was in great condition with about 300hrs, custom ballast, etc. I’ve seen the same boat in worse condition with less options listed for $40k recently. With the cost of new wakeboats going up and up, the resale market for wakeboats has done the same. I actually made $ on my Avy after about 7yrs of ownership. That said, you could make an offer at $20-$21k or something like that citing the issues you described above. Worst thing that can happen is he says no.
The high engine hrs are expected for a boat of that age, but would be the most worrisome part of the deal to me. It might be worth the peace of mind to take to a shop for a compression test/overall checkout.