Should we disregard our father's will not to deal with our paternal aunt and her children if we communicate with them, especially since our father is bedridden and unable to speak?

The father erred in his will by severing ties of kinship, because it is an unjust will and contrary to Allah's command, therefore it is not permissible to implement it. What is obligatory is to maintain ties with the aunt and treat her kindly. If one fears the father's anger or worsening of his illness, then it is obligatory to maintain ties with her secretly while advising the father and reminding him of maintaining kinship ties.