Properly charged and functioning battery, good glow plugs, fresh clean fuel filters are all critical for cold climate hastle free starts. Was the the Florida car fitted with a block heater by the dealer? If it was not ....have one retrofitted for a little extra protection during sub zero night temps.

I agree with Marty and I may have said it before....SNOW TIRES will transform the E300D or TD from handling like a sloppy tobogan to carving corners like a bobsled on ice and snow. Your son's life and the vehicle are worth the $650 for a set of severe weather snow tires mounted on their own designated winter wheels (steel). Up here in New England....run on them from December through March. Let it snow..let it snow...let it snow!
Cheers

__________________
FRED

Daily Driver: 98 E300TD 199K
Hobby Car: 69 Austin Mini
Past Diesels: 84 300SD, 312K
87 300SDL, 251K
94 Chev. K-1500 6.5Ltr.TD, 373K