If Japan wants its aging population taken care of by humans (as opposed to creepy dystopian robots), it needs to do at least one of three things
1) Ease immigration rules now and open the floodgates significantly. You want immigrants to start working now and start gaining cultural and language skills ASAP. You also want the immigrants to start families in Japan so that you have a new generation of people who are fluent in Japanese.
2) Send out Japanese teachers en masse all over Southeast Asia and teach the people as much Japanese as possible so that they are semi-literate and semi-fluent when they arrive in Japan to work.
3) Organically create a creole or pidgin language by which Filipinos (and other immigrants) and the Japanese can share an English-like language. The Japanese already have a large English-based lexicon so they already have a running start.
The Japanese need to accept the fact that a racially and culturally homogeneous society is just not going to work, unless they want ASIMO to change their adult diapers in their capsule-filled nursing homes.