It's difficult to comment on issues of this kind, given the new standards regime so recently introduced by the government. There is little experience of its working in practice, and in any case, councils are free to choose their own standards provided they conform to some rather general principles.
The general principles appear to be rather tightly drawn and to focus on the interests of the council member. It's hard to see that in your case the councillor could be shown to have a pecuniary interest in the appointment, or any strong enough interest to have committed an offence.
Having said that, my own feeling is that it would be prudent and wise for a councillor who has any kind of personal connection with a candidate for employment to stay out of the process.