The use of "torrents" can be a potential minefield I'm afraid.
There is nothing inherently wrong with torrents from a technical perspective, but unfortunately bad people will often "spike" files with malicious code that are downloaded using torrents and that is a major vector for the distribution of viruses, Worms Trojan Horse infections and a whole host of other nasty stuff. These bad people use "spiked files in a way similar to that used by bad people in bars or nightclubs that may attempt to spike someone's drink in an effort to take advantage of them.
Torrents will sometimes seem an attractive way to download movies or music files or software files without having to pay for them!, but often they come from unknown sources with questionable provenance, including those that may have legal consequences or infringe copyright etc.
I'm sure that your son and daughter in law would be horrified to hear that they may have inadvertently worried you, but the whole subject of torrents is a potential minefield and I think it would be wise for you to uninstall any programs/applications that may have been installed for using torrents and delete any files downloaded via them ( unless 100% sure of their provenance.)
Here is a link that may provide you with more information:
If you would like to have your computer checked for malicious code then open a new topic in the Virus and Spyware removal forum and provide a link to your topic here.
Please don't be unduly alarmed, but it would be best to uninstall them and steer clear of them for the future.