I figured it out, I know who Jackson’s dad is.
It has to be Jack Harkness. Cause Jackson would flirt with anything and he has obviously some 51st century pheromones working for him.
And so he’s parents are not dead they just had to fake their death and go work on some Torchwood business or whatever (I’ll leave to your imagination who is mum is). And they left Jackson in Beacon Hills so he would be safe and hidden whatever they are working on.