The development and analysis of many new behavioural treatment programs over the last 30 years have led to three major advances. [One, start young; two, we can identify the subgroups who gain the most;] Third, advances in the teaching of socially appropriate forms of communication are associated with concomitant reductions in self-injurious and other destructive behaviours in the majority of students. Because of this concomitant reduction, the use of aversive interventions to reduce destructive behaviours may no longer be necessary.
In this context, 'may' screams weasel word. He's still not willing to back down completely.