Thank you for your response.
Please do accept my apologies for my delay in responding to you.
As your parents are still currently together, then your mother would have to petition for divorce of the basis of your fathers unreasonable behaviour. This is often referred to as a quickie divorce otherwise she would have to wait 2 years if your father agreed or 5 years if he did not.
For unreasonable behaviour she needs 6/7 reasons as to why they can no longer remain married. These are subjective to your mother such as he didnt pay her enough attention etc
Your father can seek to contest the divorce and the reasons used by your mother but his ill health is not a reason for delaying or contesting divorce.
Contested divorces are rare as in reality once one party has issued divorce proceedings it is really a sign that the marriage has broken down and courts will often grant the divorce even if this is contested.
In relation to the matrimonial finances - this is the assets and liabilites for both of them. The starting point for division with such a long marriage is equality. Your mother may argue that his ill health means he needs a larger share of the assets this could be around 10% more.
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