Unfortunately your best option is to wait until your father passes away and then sponsor your mother.thank you for everyone post
the reason i ask this is the doctor said my wifes father only have 1 or 2 year left (which is very sad, and he is suffering)
and of course we wish it will be more than 1 or 2 years, pray hard.
therefore, if i put only her mom on application, i dont know if CIC will ask why i dont put her dad as well and with her dad condition, i think CIC will reject for sure if i am luckily to get picked.
Therefore our whole intention is just to sponsor her mom .