Yanagida's mother Kayano is being flown from her home in Kyoto to Auckland and is expected to arrive on Friday morning, with New Zealand Thoroughbred Racing assisting her to make the trip.
Yanagida's close friend and fellow Japanese jockey Yuto Kumagai, who, like Yanagida, lives in Matamata, has been the contact for Yanagida's mother, who does not speak English.
"We are very upset for her and for Taiki and all we can do is pray," says Kumagai.
"He is my close friend and has taught me so much and looked after me here.
"He is very tough but it was not a good fall so it a very hard time for all of us. I hope people pray for him because he needs our help."
Yanagida had a personal best season last term, riding 42 winners to finish equal 15th on the national premiership.
"That is simply down to hard work," says O'Sullivan.
"Taiki came to use without much riding experience but worked very, very hard at his job and kept getting better.
"Part of that is because of his extreme dedication to his fitness. Being quite tall for a jockey he never shirks doing the hard work running he needs to and is a bit of a fitness fanatic.
"He is a good young man, a really hard worker around the stables when he was our apprentice and even though things were quite grim up at the hospital today we are hoping for the best."
Yanagida, known to almost everybody in the industry as Tiger, has ridden 162 winners in New Zealand including five at the elite black type level.
He rode Rusavy to win race five at Wednesday's meeting, just two hours before the accident.
