Friends stolen bike - identified and thief arrested

[On Holiday]

My friends dad had his bike stolen earlier this year, long story short;

He left the keys in it, went into the shop about 10feet away, lad jumped out of a car, jumped on bike, stalled it then rode off.

Insurance say they won't pay anything as the keys were in it, but now that they've caught the thief and my friends dad has identified his bike - what can he do to get it back/claim costs off the thief if possible?

 

[On Holiday]

Yeah I expect that, but end of the day, he's obviously learnt his lesson? It's fair on the insurance to say they won't pay out due to keys left in it.
But with the bike thief caught (on bail) and the bike possibly still in one piece, just wondering what options he'll have now?