Is anything required of us after the loss of tapes that were supposed to be distributed?

The trustworthy hand is not liable for guarantee unless it transgresses or falls short, such as the hand holding a trust (wadi'ah), a loan (a'riyah), a lease (ijarah), or an agency (wakalah). Transgression means doing what is impermissible, and falling short means neglecting what is obligatory. As for the untrustworthy hand, such as that of a usurper (ghasib) or an unauthorized intervener (faduli), it is liable for guarantee even if it does not transgress or fall short. The hand of the questioner's sister is a trustworthy hand, so she is not liable for the tapes unless she transgresses or falls short.