What type of parent is Polonius in Shakespeare's Hamlet?

I would call Polonius a parent of unwanted advice.  Polonius, of course, is the fool of the play, so this description should not be surprising.  Because Polonius is mistakenly killed by Hamlet fairly early in the play, there are only a few examples to which we can point.  One is the very famous scene where Polonius gives Laertes advice upon leaving for his trip abroad.  In this scene Polonius obsequiously follows Laertes as he is getting ready to go.  What follows is a list of pointless advice such as "a borrower nor a lender be."  This advice is found within a long and rambling dialogue where Polonius is the one who speaks most of the time.  Further, it is Polonius who suggests that Ophelia spy for the king.  Ophelia has previously been in love with Hamlet and has misgivings about doing this kind of dirty deed.  Due to Hamlet’s emotional instability as a result of the break-up between the two (and perhaps as a result of her own guilt for spying), Ophelia loses all of her mental faculties.  Consequently, the unwanted advice of Polonius can be seen as the indirect reason for her insanity.