::Rant on::
I feel like this is another example of why "open hardware", especially whole complicated product designs, is to a large extent a lie anyway.
(By lie I mean having a chance at recreating the device by yourself)
Take just one piece here. Say they gave you the cad files for the injection molds, AND you happen to either be an injection mold expert or have an amazingly excellent relationship with an injection molding company that is willing to stop all their other paying work to help you try to make a ventilator. Great. How long does it take to have the dies machined for your specific injection molding machine? How long to get the dies modified after they come back and don't work the first time (and likely second time)? How much machine time and material cost can you dedicate to this side project? And this is all assuming you already knew what you were doing. Your average garage hacker has a zero chance of success here.
The same thing goes for essentially every part of a machine like this. Metal parts need a machine shop, which means stuff like fixtures and CNC programs (more iterations). Electrical parts need PCBs and components sourced, and stencils, and pick and place programs, and bed of nails fixtures (more iterations). You probably need a fairly complicated final functional test setup that involves references like specific O2 concentrations and calibrated flow rates (more iterations). All these manufacturing processes are iterated over many revs before the bugs are worked out at a serious cost of time and money and man hours. What's the MTBF? Once a design is rolling in production you don't make any non-essential changes (part substitutions, vendor switches, skip procedures) because you can't foresee all the consequences but you think some garage hacker can get all this working in a short period of time. This thing needs to run 24/7 and CAN NOT FAIL. Can you ensure that? Oh yeah, and did anyone mention that some places are already at their peak ventilator demand now and others will be there in weeks, so you have to sort all this out by yesterday.
Again, garage hacker is going to fail here even if they have 100% of the manufacturing design files. Even big companies that make products with related processes is going to fail at immediately recreating someone else's design before they go through all the manufacturing process iteration.
Making a medical device has a seriously high bar for a reason! The consequences of failure at any step here is that you may kill someone who otherwise might not have died. That's not helping. Any medical professional that has to debug your ventilator in the field is wasting time that could be saving someone's life.
Like Dave said. A big chunk of this is mechanical, and he's not a mechanical guy, so this isn't what he does. It would be so much easier if all the garage hackers could come to the same conclusion and stop this "lets build a ventilator" stuff.
If you actually want to help now, go volunteer delivering groceries to some old folks.