My parents are old. My mother is not very well, I do not think she will be with us for much longer. How can I make this last period of her life as pleasant and painless as possible?

The mother showsyou about your own relationship with the material aspect of the earthly dimension, because it is through the mother that the Divine Being incarnates. So everything about the mother tells you about the material aspect of the earthly dimension.
Your father tells you about your orientation towards Life, which if lived in a duality becomes need for approval: therefore the need to be approved from the outside in order to recognise oneself.
Now what the reality of the version of your mother is communicating to you is the need for finding peace in the material aspect of this earthly dimension by letting go of everything that is categorised as suffering.
Suffering comes from lacking. So the more you recognise yourself as a Divine Being, recognising your wholeness, therefore no lacking of anything, the more you will intercept in the Infinite Possibilities the version of your mother consistent with this, therefore free of suffering. 
Is it clear for you?

I am trying to understand as my mother’s suffering is predominantly physical suffering.

It doesn’t matter. You tend to separate, but physical suffering is the manifestation of a kind of suffering that is not physical. So what you see in your mother and to whom you give a physical cause, in Reality it is the manifestation of your inner suffering that manifests itself through the manifestation of your suffering mother.
If you accept the vision of the Absolute, everything you observe outside of you becomes clear to you that it is a projection of what happens within you. Otherwise you will continue to look at life as “mom is sick, everything is external, everything is separate”. But in Reality it is not so. It is not right or wrong to observe through the eyes of the Absolute or through the eyes of duality: it is only experience, but you are ready to make a different choice. Doing it or not doing it is in your free will and whatever choice you make will be right for you.
Is that clear to you?

I can’t understand how what I choose, what I believe, what I am, what I embody right now can create what my mother is going through right now, which is physical, she is crooked, she broke both her legs, She’s constantly in pain …

Because you continue to think “I create” according to logic on the material plane. But if you were to open yourself to the vision of the Absolute, you would only see a projection of your suffering with respect to the material aspect of the earthly dimension, a “do not be inside”, a “feeling that there is much more but remain trapped in the dual issues” which is manifest through your mother’s troubles and sufferings.
That doesn’t mean it’s your fault, okay? You don’t have “fault”. Guilt is a human invention. Actually, it’s just a projection. But you are responsible for the life you live and, at the same time – and the human mind does not understand this – at the same time your mother is treading her Path, and her choices have created her reality. So for you the responsibility is to intercept in the Infinite Possibilities the version of your mother who is fine, is not sick, still has a lot to give; or the version of your mother who even with the physical ailments she has no pain; or the version of your mother who … Infinite are the possibilities, for all is One and all already exists. But if your observation continues to be in cause – effect, you will continue to observe your mom who is old, who has that pathology, who can do nothing but … because … because … because … But you are the All, You Are Oneness: opening up to this possibility, opening up to this vision, that is your Path.
So don’t hurry, don’t stop, watch and listen to your What You Feel Deep Within Yourself.

Excerpt of a Channeling from the Source session
of 10.01.2024