I worked in the textile industry for over 25 years, "kapok" is the seed fibre obtained from the tropical tree of the same name, and was previously used for e.g. stuffing soft toys. What MMC used is more likely to be compressed "coir" fibres, they are derived from the outer coat of the coconut, and are used in e.g. door mats. Antique furniture/upholstery restorers sometimes use a layer of "horsehair". The MMC stuff is definitely not asbestos though.
