Tricky question :) but I guess your corporation will loose standings at next downtime…
As I understand standings mechanics: since you have no standings at all you wont influence anything :). Next, corporation standings are calculated as average standings every seven days, and after a week they will be updated at every downtime. So, if I got it right, next downtime when your buddy leave corporation standings will be neutral again (since you are only member of corporation).
If you are doing all this in order to anchor POS in high sec space, your POS can remain anchored even if your corpmate leave.
Anyway, here is full description but there is only one way to really check this ;)
PS. I’ve noticed that sometimes, usually after applying expansions or patches, corporation standings can be calculated faster ie. you dont have to wait for a whole week.