Yep given this is Austrian jurisprudence they should be able to apply Radbruch. Could it be overturned on appeal? Sure, but the judge also wouldn't look stupid on appeal. German courts are using it in instances like conjuring a Romeo+Juliet exception out of thin air (in the "sex on your 14th birthday with your SO who is still 13" kind of sense), directly contradicting written law, saying "yep they overlooked that corner case". Law didn't even get updated as application of the formula is so uncontroversial.

In particular, this letter-of-law interpretation ignores equality before the law -- that between natural and juridical persons. You need a proper reason to do such a thing. Quoth Radbruch:

Where there is not even an attempt at justice, where equality, which forms the core of justice, is deliberately betrayed in the laying down of positive law, then the statute is not even merely 'flawed law'—rather, it lacks completely the very nature of law. For law, including positive law, cannot be otherwise defined than as a system and an institution whose very meaning is to serve justice.