Hello and welcome,
I am so sorry for your Dad's problems. I would like to suggest you get a second opinion from another Dr. regarding his care and how to prevent further strokes. Yes, clots from the heart can break loose and migrate to the brain causing a stroke.
Many people who have heart surgeries, strokes, blood clots or heart valve replacements take blood-thinning medications in order to maintain proper blood flow.
Anticoagulant medications help prevent the formation of blood clots by increasing the time it takes a blood clot to form. They do not dissolve the clots present by using a blood thinner.
Once a patient begins taking an anticoagulant medication such as the prescription drug Warfarin, also known by the brand name Coumadin, they need to have their blood analyzed frequently.
Anticoagulation therapy requires regular monitoring because high levels of anticoagulants increase the risk of bleeding, while levels that are too low increase the risk of stroke and heart attack.
Please advocate for your Father and ask for explanations before and during procedures.
I wish you the very best.