Drop the 'él' (or don't, but it's not going to be necessary if the people talking know who they're talking about) and change 'al' (a+el) to 'a'. If you're saying that he resembles his father (su) then 'el' doesn't need to be there. Including it is saying “He looks like the his father."
i have the same question - se reflexive can be to him, her or it but not sure how that relates to the sentence "El hijo se parece al padre.". for instance, i understand how "Ella se quiere" means she loves herself -se provides the herself context, but not sure what context se provides with "El hijo se parece al padre."