If I filed my taxes with a family member, how can I find where they were filed to?

What do you mean by "where" they were filed to?   If they filed a federal return it went to the IRS.  A state return went to your state.  For details, ask the family member what they did.

I highly recommend that everyone create an online account on the IRS website to verify the status of returns, payments, refunds, stimulus information and so much more.  You should be able to verify details there. 
 

Click to create an IRS Website Account.