Suggestion with stray cats

Good day. Apologies for not being able to speak tagalog as I am a foreigner. Also please move this post to a correct section if it is posted wrongly here.

My in laws are based in Metro Manila. My mother in law looked after a few stray cats some years ago and people have been leaving strays at their house anonymously because they know she will look after them.

There are currently about 20 cats in the house now but she has gotten older and is now struggling to care for them. She has been looking for people to foster/adopt the cats but this has been difficult as she wants to ensure the cats will be cared for and not abandoned. We have considered putting them in animal shelters but she also doesn't want them to be abandoned or put to sleep if no one comes forth to adopt them.

Unfortunately neither my wife nor I can help take care of the cats as we are not based in the Philippines. Can anyone provide any suggestions or ideas or similar experiences so we may know what are some of our options please.

Thank you and God bless