Many years ago I used to have a radio show in Ireland and when Leon toured the UK his record company asked me to do a telephone interview with him.
The buzz in the UK at the time (no doubt encouraged by the record company) was that he was, in fact, Bob Dylan's brother.
During the interview I asked him if there was any truth in the rumour. His answer, like most of his conversation, was rambling and inconclusive.
I haven't heard any recent recordings but I would expect that his wondeful voice would get even better with age.