Matt is such a great guest for the dad-isodes!
My suggestion for the next email is to turn it back round on your dad. Something like how Kat has so far managed to keep Keith at bay regarding the emails he requested to see but now she suddenly received a legal notice to hand over all emails pertaining to communications with father Malley esq. (or whatever) to a firm representing Keith.
"I don't know what he wants to do with them, but my lawyer friend had a look at the notice and tells me I could be in serious legal trouble if I ignore it! Obviously I don't want to send them our emails, with everything you did for me, and us professing our feelings for each other (
keep rubbing this in, the fucking creep!) but what do I do now?? Any advice?"
Maybe end it with "I'm sorry to keep relying on your advice so much in these nasty matters but I'm so glad you got back into my life to be there for me in times of need! I will NOT forget that!" (hint hint?)