I've read off of this site that passing a home test is not as accurate as a regular drug test. It is always a good idea to take a home test before a drug test to see where you stand but I don't think it is nearly as accurate (possibly same cutoff points etc).

Now I don't know your situation but considering that you are getting tested by your Dad i'd think that even if you messed up the dilution method you'd be alright. It's not the equivalent of failing a drug test for legal issues or for a job so getting a negative dilute would only buy you more time.