Problematic inheritance

A person died without donating or writing any will before, so French rules of inheritance applied. (which obviously differs from sharia rules)

She left a husband, 5 adult daughters, many grand children, 3 adult brothers and a mother.

According to our calculations, her effective Wuratha are : her husband (23%), her 5 daughters (12,3% for each) and her mother (15,5%).

Her mother is currently ill and senile and cannot speak. She is conscious but she mostly doesn’t communicate, even with signs. Sometimes she make some head nods but even the closests don’t know if it means yes or no or whatever…

Now this person left a company share, wich according to the law went for her 5 daughters. Her husband gived his haq to their daughters but now the part of her mother remains.
Currently every daughter is periodically discharging to her this part of the share.
But next it can become more difficult: for example if one daughter dies, her part is going to her heirs. So everyone of them will have to discharge to Aisha’s mother her due. And if she dies, they will have to periodically distribute it to her heirs… and so on.

Another issue is that thos person was co-owner (with her husband) of the house they lived in.
So her mother is owning now a share of that house.

And last issue is these goods in the wirathat which cannot be distributed equally.

Question 1 : Who is responsible for this person’s mother finance ? (she has 3 adult sons and many adult brothers)

Question 2 : Can this responsible sell (or exchange) her problematic wirathat (company share and house share) to the other heirs ?

Question 3 : Can he choose which goods to take/not to take for her, Or instead he has to take the value of her share of the goods, Or is there another way?

Barakallahu fikum.