I referred the new instructions in this link,Don't want to scare you but they should have started using the new thresholds immediately in June so you would think you would have been assessed by the new threshold. Given your child's unique situation there could be more research being one because I would have though you would have heard by now.
https://www.canada.ca/en/immigration-refugees-citizenship/corporate/publications-manuals/operational-bulletins-manuals/standard-requirements/medical-requirements/refusals-inadmissibility/excessive-demand-on-health-social-services.html
My understanding is that once IME is completed and cmau adjudicates medical results based on IRPR subsection R1, the case is forwarded to the designated officers to apply new criteria.
Not sure if I am over-reading or misinterpreting this.
"Once an IME is completed, officers delegated to overcome an excessive demand inadmissibility finding, through the consideration and application of the public policy and under the authority of section A25.2, may grant an exemption from paragraph A38(1)(c) (medical inadmissibility due to excessive demand on health services and on social services) to the foreign national"