The Rosary is a very powerful prayer. Just an anecdote here, but some 20 or so years ago my son was in the hospital with a very serious concussion. He had fallen and had been in a coma for 4 days. My mom and other relatives and friends were praying the rosary constantly for him. Right at 5 pm, my mom was in his room in the ICU and another friend was just getting off work and had gotten in her car around 5:05. The friend started praying the rosary again once the she was in her car. My mom said it was right at 5:05 when my son woke up and asked my mom where he was. Is there a connection? Can't say for sure. I think the rosary is just as plausible an explanation as anything else, especially with a head injury. But he's alive and, except for some very minor balance problems made a full recovery and is now 31 years old.
One more anecdote... A few years ago we desperately needed help in getting my wife transferred back home from her job out of town. I would work sometimes in the Texas Rio Grande Valley and there I made a serious of visits to the
Basillica of Our Lady of San Juan Del Valle where I prayed the rosary asking for the help. I would look around at the incredibly poor people that came from not only South Texas but from Mexico and were all praying so fervently. I felt very guilty even asking when the people around me had so very little and had very hard lives compared to ours. Nevertheless, through an incredibly improbable series of events that unfolded over a few months,(people 3 and 4 degrees away unexpectedly retired and transferred creating an opening closer to home for her in the shuffle), she made it back home.
Yes, the rosary is a very powerful prayer.