Actually, that makes it all so much easier for you. Because when you give him negative feedback (which you really NEED to do) you can also say nice things about about how fantastic and engaging he is in the classroom. I find it much easier to deliver criticism when it's part of a balanced feedback. Teachers have strengths and weaknesses like the rest of us.
I just replied to him and I probably spent more than 45 minutes crafting an email to him!
I also told him that she hadn't had direct instruction in writing research papers for Science before and that she hadn't received a lot of direct instruction in writing or that many other writing assignments in school this year (outside of Science).
yes, but you care about the email.
I think the part about never receiving instruction on how to do this is really important. If over the course of this year, he really teaches the kids how to write simple science papers, that would be a good thing. But it is unreasonable to simply assign work without teaching how to do it.
I think there is a big difference between a 2-3 day assignment and a one night assignment. A couple of days allows for kids having one night a week that is busy, or needing some time to mull over their research before doing their writing.