Luckily, the Liberty Coalition of Canada is actually keeping their correspondence (I'm sure it isn't everything relevant, but it appears to be most of the stuff they have from their interaction with the school) available on their page about the case.
https://libertycoalitioncanada.com/liberty-defense-fund/josh-alexander-v-rccdsb/
There they have a letter from December concerning the November suspension. (warning - it is a pdf:
https://libertycoalitioncanada.com/...ecember-20-2022-Suspension_Josh-Alexander.pdf)
You can see the school's argument somewhat in that letter.
Alexander was temporarily suspended pending an investigation into whether or not suspension or expulsion was warranted.
(Remember, this is after he had come to the Principal and demanded the rule be changed, then started organizing a protest. The school seems to have had other complaints about his behavior and so investigated.)
Alexander and his parents refused to meet with the School officials or otherwise help with the investigation.
The principal decided that expulsion was unwarranted, but Josh should get an official suspension of 20 days listed, which he had already served.
He was welcome to come back to school in January as long as he didn't dead name students and he didn't attend the afternoon classes that included the two students who the investigation had found he bullied or harassed.
Josh's lawyer responded that they would refuse to accept those terms.
The principal then said he couldn't come back.
Josh then came back on the first day of school, skipped the two classes he was told he was allowed to attend, and showed up
only for the two classes he was told he shouldn't attend in person. He showed up with a camera crew and with no class materials.
He also appears to have refused to talk to the school's teachers and student support services, which have reached out to try and organize the best way for him to get his full education and have specific support for the courses he is missing class time in.
There also appears to be a weird thing where he and his lawyer are insisting he has removed himself from parental control but only for the purposes of appealing the suspension.
This doesn't appear to be legal in Ontario. His parents can appeal his suspension for him, but they appear to not be willing to do that. Either that or the lawyer is specifically doing this so that the appeal can't actually be heard and they can claim to be martyrs because the province won't even let them appeal.
So further reading makes this really look like it is just someone who is not looking for a solution, but looking to escalate as an activist for the press coverage and to political pressure.