I do think you are being a little unrealistic.
talk to us parents about his areas of weaknesses as identified by the assessment
your child is 17, not 7! at 7 these things re discussed with parents at length, at 17, not, unless intellectually incompetent.
- share the assessment so we are better informed
you say you already have a copy of an old assessment, ask for a copy of the recent one, it will be a lot shorter.
- assess his learning difficulties and strengths
This will happen in class, as with all students in the class, to an extent, although he is at the age where everyone is expected to be able to do that for themselves. No one is going to go through all of someones strengths and weaknesses in the kind of detail you seem to think you can expect.
ensure the way he is being taught takes account of his difficulties
what ways do you think he should be being taught that he isn't at the moment? Again, I think you think there is some sort of magic formula that should be being applied, there isn't. He has some problems with reading and writing, he needs to work longer and harder to over come them, that's it really, and use any little strategy that he finds helpful.
-have an action plan and share with parents
Again, plan what? What plan do you think you want? and as to share it with parents, again he is 17, so that is entirely at the discretion of the school, and depends on time and manpower available, plus full permission from your son.
review impact of various strategies and try different strategies if not working
again, he is 17, you are talking as if he were 7, he needs to find his own best ways of working, as do ALL students.
engage with him regularly and be aware the impact on his mental health.
do you think teachers are not engaging with him every day? in what way is his mental health more vulnerable than that of any other student? Does he have mental health issues too? That is a totally separate thing, and likely to be recorded and monitored by pastoral, not SEN.
I hope your DS does well, but I do think you are not being very realistic with your demands. Dyslexia is not a condition that automatically qualifies for any support at all, it depends on the extent, and the type, etc. In fact, dyslexia isn't even a clearly defined condition at all. There are no "plans" and " strategies" for dyslexic students, they have weaknesses in some areas, as does every student, except theirs are likely to be more pronounced, however, as every student, they need to work on their weaknesses, and find out what ways of working most helps them.