JUST to be on the safe side, copy all the important stuff from your dads drive to a cd or dvd, or just in case send it to your self thought gmail.
Other wise from what i have known you have a very very very slim chance of lossing both of your data.
If your dad has like office work of something i wouldn't risk it, caz i did it once and totaly crapped out...
YES, but make a few diffrent backups. CD DVD EMAIL ECT
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