There can never be a proper fix to this problem while the floor slopes away from the drain, because an alarm of any nature relies on someone hearing it - and acting to clear the drain blockage in time if no other egress for water exists. Rain can arrive anytime and in unbelievable quantities, especially in these times of unstable climate. The answer for a 100% cure is to regrade the floor with a sand/cement [ or gypsum but I've never heard of this use before?] screed to proper height and falls of say 1-100 and sort out a proper engineered drainage solution. Since insurance will not pay for any future flooding, a basement sump pump to back up the gravity drain is probably the best option. But as the owner seems to be retreating from reality, even in terms of the cost of a few dollars worth of trim, I doubt any advise will be heeded anyway.
You can't educate pork.
