If they are going down the route of Albie having a genetic illness, I can only see that meaning Phil is his father. Otherwise what’s the point?
I do think Sharon knows that Keanu staged the kidnap.
I can envisage her going along with all the wedding plans, then in front of everyone on the day, she will say ‘Did you really think I would ever marry you, you spineless, cheating, lying, stealing, pathetic mummy’s boy. And Albie isn’t even yours anyway’
(but I don’t think he will be the body, he will just leave in disgrace)