Yeah, before him they were trending downwards 92 points in 08-09, 90 in 09-10, 87 in 10-11 and started 6-7-0 in 2011-12 before he took them over and they rebounded to 109 points in that season.
After that he led them to put up 60 in the 48 game season, followed by seasons of 111 points, 109 points, 107 points but they had started to stumble in year six starting out 24-21-5. Yeo rebounded them initially going 22-8-2 after taking over, but the drop continued to 94 points last year and you see how this year is going.
I'm pretty confident he can improve this team, just remains to be seen whether it's enough for playoffs or not. Obviously, the Blues team he picked up was much closer than this Oilers team is, but he also brought them from being just outside playoff contention to a perennial top 5 team. Then last year he brought a lottery team within 2 wins of playoffs, so I don't see it unreasonable to think he can get them playing meaningful hockey in March, possibly even April, particularly having McDavid as likely the best player he's ever had in his arsenal.