Multaq and Pradaxa for A fib

My dad is a 69 years old, and had bypass surgery in '04. No heart attacks. He does have a leaky valve, doc doesn't seem to concerned with that. Recently, he went into what they called a "controlled a fib. Dad was not symptomatic, just checked his bp one day, wasn't what it normally was, it was high and his pulse rate was high. They put him on blood thinner and cardioverted him. He is now on Multaq 400mg twice a day and pradaxa. He is doin good so far on the new meds. It just concerns me reading some of the reviews about Multaq. Liver damage, heart failure, etc. Should we ask his cardiologist for another alternative med? He has been on the Multaq for almost a week, and like I said, so far, doing great. bp is good and pulse rate 50's and 60's. Any guidence would greatly be appreciated. God bless...