welcome to healthcareMagic forum..
Open heart surgery is usually done if a patient has a triple vessel disease
where in major arteries of the heart are blocked.
is done for patients where in only 1 or 2 of the vessels are bocked..So based on the severity of the disease of your father the doctors might guide you to under go a open heart surgery or angioplasty.
Expenses will depend on the hospital.So u need to call them up and find out!!
Hope this helps!!