WHY DIDNT ERIC'S SIBLINGS AND FRIENDS APPEAR IN THE MOVIE?

What happened between Cornelius "Corey" Matthews and his brother Eric?
I bet if Shawn or Topanga got into trouble he would have been there for them.
Eric should have followed Mr Feeny´s advice and gotten a better college education.

Stuart Minkus (AKA Stuart Lempke) could have also made a surprising cameo appearence to help Eric(he dissapeared for four years and suddenly appeared for the graduation) Corey and Shawn asked him where he had been all the time and the reason given for his absence was that his class was on the other side of the hall with Mr. Turner.

I know that you´re going to say that they are different Erics, but remember that Corey and Eric´s sister, Morgan, was also played by two different actresses. Upon her reappearance, she said "That was the longest timeout I ever had!".