Lachlan had feared that Rebecca would reveal he was the one responsible for the crash that killed his mother Chrissie White (Louise Marwood) and his grandfather Lawrence White (John Bowe).
But his aunt’s amnesia saw her place the blame with Robert Sugden.
Whilst she recovered from the ordeal, her baby Seb has been placed in the care of Lachlan – with Beth Dingle helping him to care for the little one.
But fans soon insisted this was a major plot hole, asking why social services would place a baby in the care of an unhinged 17-year old.
Lachlan was also charged with attempted murder after he shot Lawrence in 2016.
And he sexually assaulted Alicia Metcalfe (Natalie Anderson) in harrowing scenes that were aired before the watershed in 2015, back when he was only 14.
One person remarked: “#emmerdale come on as if social services would let baby seb be looked after by two teenagers one with schizophrenia and one just out of prison in a half derelict house #far fetched.”
While a second commented: “Come on #Emmerdale no way wound Lachlan be allowed to have that baby he's a convicted sex offender ffs.
"Also where's social services cos in real life they'd have been there from day 1.”
And someone else wrote: “Now, this would be grounds for calling social services.
"Making Lachlan Seb's caregiver is dumb enough but if she remembers him hiding out in the attic surely she remembers Lachlan throwing a remote at him.”
Rebecca was left fighting for her life in a coma after her nephew Lachlan deliberately forced the car carrying his entire family off the road.
Some fans fear Lachlan may be planning to seek revenge by taking Rebecca's baby away from her.