Well, for one, many other places haven't budged off their 100 hr multi mins.

Not so. Some have gone down to 50, SKW being one.

I'm very disheartened to read the replies here. I agree, someone with ATP mins should probably look at a regional with jets and better pay. However he has 1000 hours and his current job is flying 10-15 hours per month. Great lakes has a 135 charter side apparently now and will hire with less than ATP mins and then move you to the 121 side when you meet the mins, and give you an ATP when doing so. I know that there may be a few better options but this is the place that called him and I encourage him to go. Have we all forgotten where we came from? I know I worked numerous very low paying flying jobs because it's what was available at the time. I wish the industry wasn't in the state that Great Lakes had to be seeking out pilots under 1500 hours but for a 1000 hour non-CFI pilot, I feel like it may be a decent opportunity. I would also suggest he look for a jet job as soon as possible.

Got a verifiable source for that? Their website still says 100 ME.

Can anyone confirm Lakes now has a 135 side? Last I heard the FAA said no unless Lakes takes the seats out the plane to make 9 total seats

I spent two extra years as a CFI to get a regional job I really wanted rather than settling for lakes and Mesa which would have hired me at 300 hours at the time. That's where I came from and that's why I commented to stay away. I guess it comes down to how much your friend respects himself vs how much he has shiny jet syndrome.

Tell him to get his ATP mins and go to a respectable airline.

Great Lakes is in dire straights financially right now, why create hardship for yourself. Just sweat it out at the teaching job. GLA is not the place to be these days, if it ever was, but especially now. However, the Lakes pilots themselves buy blocks of simulator time at Advanced Aviation Simulators (on their own dime) at KAPA in Denver. The latter firm is highly recommended.

If he needs instrument prep, do a few approaches that's all you should need to do. If this is where he wants to start to look good for other flying don't fault the guy for getting started somewhere.

The problem is here it is likely to backfire on him. Going to an unstable company where the retention is known as truly terrible, and washout rates are known as high during training, how good does that actually look to the next employer when your damaged goods finally land there? And what's worse, his training records will go along as another undue risk. This is not a smart career move for a newbie who is sick of instructing. The dream of flying heavy metal (9 seaters :)) needs to be tempered with caution and due diligence.

From what I understand the 135 cert has been approved for some operations, heard they will be placing straps over extra seats to comply with the regs. Expect a different contract if you are planning on building your time from the 135 side, last I was told it would be a 3yr, 17k deal that would prevent you from jumping ship.
Honestly it's not what it has been, most pilots have left now that negotiations have pretty much halted and it appears the company refuses to make anything better. The shortage of FOs is so severe I wouldn't expect an upgrade.
The idea of getting time fast is appealing, however consider the situation that lakes currently faces and what that means to you. When an airline is in dire need you often face situations where making the right decision can be difficult. The time you quickly attain to "get ahead" may be less valuable if you end up with an action against you.
Explore all options, if Lakes is what works best then be smart, do your homework, and have fun on the 1900.