I think one important reason why your boss ask you to interview this person is that you may work with him/her in the future. From a team member's perspective, behavior questions such as:

1. give an example of collaborating with other team members to solve a problem in previous projects
2. give an example of supporting other team members.
3. give an example of supervising other team members.
4. give an example of resolving conflicts(being convinced or convincing other)while having different opinions with team members.




might be appropriate.