Legal Question in Criminal Law in Tennessee

It sounds like your brother was given a sentence of "life," with eligibillity for parole. He will be eligible for parole in 51 years.

Yes, the rules in effect at the time of the offense govern punishment for the offense.

If the rules are more favorable to him at the time of sentencing, he is generally entitled to the rules mose favorable to him: Those at the time of the offense OR Those at the time of sentencing.

And under some circumstances he can "waive" the old rules and elect to have his sentence

executed under the new rules.