I have a question about the Buddhist altar that was in my parents' house.

The mother's admission to the facility is probably sad, but since it's probably a place with good facilities and environments, there are aspects where you can rely on it and feel safe.

Also, you're thinking about holding a memorial service yourself, aren't you? Since it's probably something with the Buddha written on it, such as sutras or sutras, I think it's better to arrange things properly at the end.
There are also online consultations on Hasunoha, so I think it would be nice if you had a proper memorial service with the monk individually.
It's safe to hand over the goshuin book to your mother.

I go to visit facilities, and there are times when the Buddha is left in my room, or I bring sutras and pray together in my room. Putting important support on soba is also reassuring. I think it's okay to talk to your mother.

For now, please talk to the temple that you always ask for memorial services about.
For me, I think the best thing is to keep it close to the parents in the facility so that parents can see it.
If you can't do that, keep it in a Buddhist altar with a plaque, or keep it for yourself to know and protect your parents' beliefs. Also, if you have to pay the coffin in the future, please put the goshuin book inside the coffin.
If you can't do that either, ask the temple to pick it up. I don't think it costs much money.
Also, you can place a sibling's smaller table with your ancestors on a relative's Buddhist altar, or if your sister wants to keep it by your side, you can use it as a space to enshrine a corner of the bookcase, or you can attach a small shelf to the wall and place it on top of it.
Depending on the temple, there may be places where they can take care of it.
Think about where you feel most at ease.

It's very natural to feel lost about what to do in front of an important Buddhist altar or goshuin book. The very attitude of trying to put their hands together with all their heart as possible is a splendid memorial service.

・About goshuin books, sutras, and sutras copy paper
Goshuin books and sutras are “proof of a relationship with the Buddha,” and you don't necessarily have to ask a temple if you don't treat them poorly.

The goshuin book can be kept in a safe place as it is, or you can put your hands together and clean it up with gratitude, saying “Thank you for the relationship so far.”

If sutras and sutras paper can be used for reciting or copying sutras, please continue to use them for daily sutras recitation. For unused portion, it is common to wrap it in white paper, recite one volume of sutras (Heart Sutra, etc.) in front of a Buddhist altar or Buddha statue, then incinerate it, or bury it in a clean place.

・About the sibling's rank that wasn't awarded

Small placards are irreplaceable proof of life.
Even if you don't have a splendid Buddhist altar, it is enough to wrap it in a small cloth or box and place it in a clean place (such as on a chest of drawers or in a corner of a bookshelf).

Even if you can't put your hands together on a daily basis, simply praying “in peace” in your heart when you remember it will be enough for the memorial service to arrive.
In Buddhism, they say “the mind is everything.” Rather than shape or location, the best memorial service is the feeling that you want to put your hands together.

・Through distance from my parents' house
Even if you leave the Buddhist altar at your parents' house, your feelings for your ancestors, parents, and siblings won't disappear. Reciting nembutsu or sutras once, and muttering words of gratitude each time, is a splendid daily memorial service.

・Summary
Goshuin books and sutras may be treasured with gratitude, or burned after chanting sutras.
Small placards can be placed in an inconspicuous place, so place them with a clean feeling.
What is more important is to keep praying “thank you” rather than form.

Gassho

I read it.
You have to get rid of your parents' house, you have to get rid of your goshuin books, sutras, and sutras, and you're also worried about what to do with your siblings' small place plates. I don't know the details, but I can tell you that you are having trouble. I understand your feelings from the bottom of my heart.

If possible, I think it would be a good idea to leave goshuin books, sutras, and sutra copies at the family temple for a memorial service.
If that doesn't come true, please mail it to my temple, and we will make a memorial service and burn it up at the end of the year.

Is it difficult to keep the cards in the room? I think it's okay to offer it on a shelf in a private room where no one can enter.
If that is also difficult, I think it's okay to carefully wrap it with a cloth and keep it in a safe place in a box.
Wouldn't it be nice to take them out in between and put their hands together for a memorial service? Also, please put your hands and hands together to do a simple memorial service for your ancestors, which is possible every day.

There's nothing you can do about it, and if you still want to get rid of it, please mail it to my temple. I will make a memorial service with all my heart and let me remove my soul.

It's fine if it's not about donations.

You and everyone will continue to cherish your ancestors and hold memorial services with all your heart, and I sincerely pray to the Buddha, gods, and your ancestors so that everyone can live a healthy and friendly life together. We wholeheartedly agree

Questions about how to handle Buddhist altars and placards that have been handed down from ancestors are frequently asked. I often hear that it's difficult to maintain it yourself, even though you know it can't be shoddy. Buddhist altars and placards do not contain ancestors or Buddha, but are enshrined as symbols of them. Since they are difficult to handle, they are often asked to keep them at temples, but please think of things that connect the client to their ancestors as Buddhist altars or place plates. Please cherish that feeling of connection. That feeling will help you support your life. You don't have to ask a temple or monk in particular, so try offering flowers to the Buddhist altar yourself, lighting a candle, cooking incense in an incense burner, and chanting short sutras. When you can feel that the power to live gradually springs up, various worries and pains will decrease. This is the original effect of Buddhism. Close your eyes, take a deep breath, then exhale deeply. If you repeat it, your pain will easily change.