Although there is no policy to govern lending n borrowing between employees, a superior borrowing from a subordinate may be seen as improper. Eventhough there is no coercing, but subordinate may feel pressured into lending. It is not healthy culture. The superior can be reprimanded for this. However, if this is the first time, you may just counsel the superior from repeating it.

I will not entertain this issue as it is more to personal stuff.