If that were true you might want to disconnect your fuse box and take that with you too. Pesky condensation might screw with your internal electronics.
Jokes aside... I beleive what your dad is refering to is condensation build up in the internals of the compressor. Compressors rated for pumping air in to the likes of diving equipment, air rifle canisters, medical oxygen etc etc up to 300 bar require the air to be clean and dry. As such these compressors have dry air filters to remove moisture from the air since it reduces the effectiveness of the seals and the volume of the canisters. This only filters out the moisture from the air before it enters the compressor, the rest of the compressor should be air tight and as such should have no
problem with condensation ingress.
Your tyres do not require such treatment. The compressor you are using is (I assume) the one that plugs in to a 12v socket to inflate your tyres in an emergency. At which point, your tyre is likely punctured and needs to be either replaced or repaired. Water ingress is the least of your worries.
I have used it on more than one occaision, but only for a trailer tyre that received a puncture whilst at the tip. Kept it in the back of my car for 6 years and its never been a
problem.
In any case, it should tell you in the operating manual for your compressor, the correct method of storage to prolong its life.