I wonder if Norman's jealousy over Bradley liking Dylan will turn out to be the red herring of all red herrings. Perhaps Dylan will turn out to be the other man in Norma's life that inspires Norman's final rage as did Norma's live in boyfriend did in the original story.
If Norma gets past the possible incest conception of her eldest son and becomes able to show him sustained affection--or if Norman perceives he's being replaced by his older, more stable and capable brother whom his first object of desire, Bradley, desired instead of him--that may be the final straw on the dromedary's back. It's bad enough that my would-be girlfriend wanted you instead of me, Dylan, but I'll be damned if you take mother away from me.
And then Norman fixes his mother and his brother a nice cup of tea.