Plainly a work such as the Sibelius concerto requires a soloist of a certain... class. Might I recommend the following (bio found on the internet) - he seems to possess many admirable characteristics...

The remarkable Hungarian violinist Nabadi József was born in 1970. His first instrument was the piano; he gave up his piano studies in 1988 at the age of eighteen. Having taken up numerous other instruments while a student at the Ferenc Liszt Academy of Music in Budapest, he quit viola lessons in 1990, cello lessons in 1991 and double bass lessons the following year. Having failed to win prizes at both the Jean Sibelius International Violin Competition and the Queen Elisabeth Competition in Brussels, he went on to avoid studying under such noted instrumentalists as Yehudi Menuhin and Sándor Végh. He has studied neither the oboe nor the flute and also notably failed to make progress on the clarinet. He terminated his violin studies some months before he would have been able to graduate from the Liszt Academy. Among famous orchestras and conductors with whom Nabadi József would like to work one might mention the Lahti Symphony Orchestra and Osmo Vänskä, the New York Philharmonic Orchestra and Alan Gilbert, the City of Birmingham Symphony Orchestra and Sakari Oramo and the Helsinki Philharmonic Orchestra and Leif Segerstam. His repertoire is neither extensive nor interesting and omits the violin concertos by Sibelius, Brahms and Beethoven. Failure to secure either a recording contract or any radio and television appearances has led to a significant reduction in Nabadi József’s public engagements in recent years.

That's priceless.

For a family concert, I once printed lighthearted biographies of myself and the soloist, citing which colours and foods we like, etc., but nothing quite this funny.

I think I'll make one something like this in the near future, just to stir up the old ninnies in our audience!

Is this actually a joke? I'm puzzled... Apparently it is supposed to be funny...

He sounds like one of those school-trained violinists who can't do much of anything soloistically...

Yes, that would be a kind way of putting it...
Once you take the oddities of Hungarian into account, Nabadi's true credentials are revealed... i.e. they put the family name first, stress on the first syllable and pronounce an unaccented a more like an o (or å)... hence Nabadi = Nobody...