Wow! Okay, I didn't mean to start a lot of bickering here, so I should elaborate and hopefully that will settle some of the tensions. First, though, I would like to point out that this isn't supposed to be a question specifically about this project and what I should do about this project in specific, but a general question about what should engineers do when they suspect another engineer, who is not in their firm, is working on a project and they do not believe they are performing responsible designs? For normal use loading, this will hopefully be apparent before anyone gets hurt, but when it comes to wind and seismic, you might not get a warning before the building either collapses or suffers catastrophic damage, and in a project like the one I am covering here, its an existing building that is unlikely going to see any retrofits in the future if they are not done today.
Yes, I am a structural engineer and this concerns the structural elements of the project. I guess I assumed this was implied, because I was talking about the structural elements in my OP, and I did sort of forget that Mechanical Engineers also includes the guys that do the HVAC and other building mechanics (very rarely do I see an actual Mechanical Engineer working on the projects I am involved in at that level, it is usually a design professional working for the manufacturer/installer unless it is a particularly specialized piece of equipment).
I'll give a quick rundown of the four pages, since I guess I'm not trusted enough here for folks to assume that when I say I think they're insufficient, they might possibly be insufficient, since this is a forum about Ethics, and not about nuanced interpretations of the building codes: page one - typed letter saying "its all good". I'm barely paraphrasing there; page two - hand written, very basic wind load calcs that only conclude a total lateral load based on ASCE 7-05 (local code is 7-10 and IBC 2015 which are dramatically different); page three - hand written, very basic seismic loading using suspiciously low dead loads (5-10 psf), a conclusion that it controls, a calc for the perimeter of the building (side A + B + C + D = P; which were incorrect dimensions, BTW), and a calc implying that the existing 120 year old brick masonry is sufficient for the shear force (no calcs for moment or geo amplifications); page four - handwritten, very basic calc, for flexural strength only, of a single floor joist, using incorrect dimensions and spacing of the joist (calc used full dimension 3x12 timber @ 16"o.c., joists are actually 2.5"x11.5" @ 24"o.c.). That's it, end of design calcs. 26,000 sqft, 15-20 unit residential apartment complex renovation in four pages. According to the contractor, there are no engineer stamped drawings. The architectural drawings predate the letter by almost a year. There will be no retrofits for wind or seismic. 120 year old brick building that has never been brought to any modern building code. By comparison, my calc package for a stair handrail bracket is as long and more comprehensive. Oh, and before I forget again; suspicious, old, mix of wrought iron and rolled steel, welded and riveted roof trusses will be seeing new RTUs. Also, for some reason there's a bunch of brick walls supported by timber walls in the roof space. They don't appear to be structural, nor a former exterior wall, they're a bit of a mystery to me, other than perhaps being a old attempt at fireproofing a space for some reason? This wasn't covered in the seismic design done by the EoR.
It also seems some folks think I/we are bitter about losing the bid. I can't speak for my boss, but I most certainly am not anxious about a lack of work. I don't know what everyone else is experiencing, but for the foreseeable future we are flat out booked and that's probably not going to change, and this project would be a huge time sink for me, not something I would be looking forward to dealing with on my own.
In my region, except in the big city(ies), there is no professional or formal review required, nor performed, for construction projects. They usually require either an Engineer or Architect's stamp, or the appropriate paperwork filled out for buildings that follow certain prescriptive guidelines (this project would not fall under any prescriptive guidelines). i.e., the public is entirely relying on the private engineer/architect for their safety.