I still don’t understand why or what takes 8-10 hours to process, can you give a moderately specific example?
Seems you are playing on the same machine that runs the server. Instead of logging out how about stay in game and activate god mode and as I said earlier go invisible or deep underground. When you play again deactivate god mode.
I realize this solution will prevent you from playing other steam games but there simply is no way around this without a second copy and a second machine.
I don’t see a solution being developed for your issue because as I read this thread and correct me if I am wrong it appears to me you are literally the only person playing this game that has this requirement.
Edit: maybe Dad sends you a message when he is done playing and you log in again? Steam does allow other games to be played while the server client is running. Log out of game client when dad is playing then log back in when he is done.