Does it seem to bother him now? It's possible it can later in life, but I would be hard pressed to do a major surgery if it's not going to impact him much. Especially if the vet thinks he can live a relatively normal life, I wouldn't want to make him go through that. If it requires a slight lifestyle change, I would do that over a THR or FHO.
I've been advised to use Dasuquin (probably spelt wrong) with MSM for joints. It's good for arthritic dogs. Water "therapy" is also a good exercise for joints. My girl's hips are relatively okay (last we checked at 8 months, may submit OFA prelims next week) and we do lots of swimming.
Can you financially afford the surgery? I know both options aren't cheap.
I do think, however, a second opinion could never hurt. I would just make sure the second opinion comes from a vet that isn't seeking to rake in all the cash s/he can.
+ Kalbi CGC 6/21/2015
+ Blackthorn's Out of the Frying Pan NW1 ORT SEN SCN BCAT SIN RATN TKN (Katsu) 9/12/2017
+ Blackthorn's Skofnung CGC TKN RATI RATO (Steel) 07/23/2018