Not all children with Autism like music. It could be with how the music is presented. I work with a few kids who really do not like music at all due to auditory hypersensitivity. The greatest difficulty is music class and they seem to have sensory overload; some of the reason may be due to auditory hypersenstivity. Two children in particular are unable to attend music at all, and we have had to develop other options for them during music time.
On a personal level, my son is on the spectrum and couldn't even listen to music (with words) in preschool, on the radio with me and hated when someone would sing him a song. He is better now. He did, however, seem not not mind classical music.
A structured, well studied music therapy program does seem like it would be good. All of my experiences have to do with more unstructured or semi structured situations (pertaining to music).
I would look up "Electronic auditory stimulation." I don't know a lot about it but it's something I do want to learn more about.
If you do hear any additional information about the music therapy please let me know. This is quite interesting. I will ask my colleagues at work tomorrow for additional information and get back to you. Too bad there isn't more empirical research data.