Does anyone here have any experience with having been (or a loved one being) on a blood thinner?

What are the pros and cons? Was it worth the risk? Does age make a difference?

My mom had a stroke a week ago. Originally, they thought it was the chemo she was on that helped trigger it, but now, after some heart tests, they are not so sure. Her heart is pumping only 20% of the blood it should be pumping, as opposed to the normal 65–70% it should pump. They want to put her on a blood thinner, but are worried about internal bleeding (with her ileostomy bag).