> me stepping in for a guy that helped found this band but...
Does he know you? Does he think you can fill his shoes?
Does the band know you? Do they think you can fill his shoes?
Do you know the band, both from in-front and back-stage? Can you work with them?
Do you need this gig?
Do they need you because they need gigs they can't fill short-handed?
How is your ego? Headstrong? Fragile?
I'm sure you know the answers, but asking us without saying these things is just going to attract many off-point (but fun!) replies.
Obviously, if you are just some stranger who walked by when the vacancy opened, the future is very unclear; OTOH if you and he and they all know each other well and all honestly feel you could work out, the Consensus Of Experts is that it probably can.
If you DON'T need the job, that's perhaps "better". Working because "you must" always colors the relationship. Being able to say "shove it!" frees you from taking crap, and often seems to work-out better in terms of a healthy relationship.
If they don't -need- gigs, there is a good chance that the loss of a core member spirals into band break-up.
But working musicians rarely quit gigging. A break-up may re-form with some old and some new players; maybe you unless you annoy ALL the old members.
Obviously you will be the New Guy, the Fill-In, the Odd Man, for the next 7 years. You have not shared the history, the hard-times, the in-jokes. In new bands and in pickup bands, that don't matter. In a crew which has hung together 7 years, it does.