Do you mean they are okay with prices in the $1000 per night range?

OK, I'll get creamed for this but the best place, overall, we stayed in in the summer HEAT was the Marriott on the Executive floor. You can walk to the train station and to Tivoli but it is not one of those charming hotels in Nyhaven if that is what you'd prefer.

LOOK at ALL the TripAdvisor reviews FIRST.

That's a good point. If you want good air conditioning, a modern hotel like the Marriott is likely the best place to get it.

FWIW, I thought the Copenhagen Marriott was a fine hotel and the fabrics they used in some of the rooms were gorgeous (and not used in other Marriotts). I was attending an event with some doctors and the female doctors also were oohing over the fabrics.
It is, as noted above, within walking distance of Tivoli although the walk isn't particularly scenic. I had no problems walking to Nyhaven from the hotel and then around the historic shopping area, but it wasn't a short walk.

The Marriott is my choice too especially if you get a room overlooking the canal. If you can get good rooms, the Admiral, Nyhavn and D'Angleterre are options but seem to be hit and miss according to Tripadvisor, whereas at the Marriott you will always get a nice room, even if it faces the road.

I also support the Marriott recommendation - for the other reasons listed above, as well as that there also are river? canal cruises that stop right in front of the hotel. They operate during the date and also for evening dinner cruises. Something they might enjoy.
The concierge there also has good recommendations for dining etc.

Thanks everyone!! It seems like the Marriott is going to be our #1 choice. But also just curious that no one mentionned the radisson SAS. Any feedback on that one??

Thanks again!!

Sorry to say this, but the Marriott is just a chain hotel for business travellers.

The best hotel in Copenhagen is Hotel Sankt Petri:

http://www.hotelsktpetri.com/

You will be stunned!

(It is brand new, so it is not listed in most of the guidebooks. But Justin Timberlake has stayed there recently. And my family.)

New it may be, but it's already got 107 reviews on TripAdvisor. Most are favorable, some raves, but also were caveats and complaints, particularly about noise (if staying on a lower floor), the party scene at the bar (having both good and bad points--as one reviewer noted: "If you don't like drunk people at your hotel, do not stay here"--and this reviewer spends a lot of time in Copenhagen, another said the hotel needs to decide if it really wants to be a hotel or primarily a nightclub).
If you do put your parents in that hotel, make sure they stay on the 4th floor or higher, as several TA reviewers complained about noise on lower floors. Also to avoid rooms 602/603 because the sound from one room carries very clearly into the other.

With the Marriott, it does get very crowded with cruisers during cruise season and it can cause some service problems as the cruisers tend to want to eat, check in or check out at the same times. My stay was not during cruise season, so the service was very good and not rushed.

The Hotel Sankt Petri is not brand new, it has been open since 2003. It is a converted department store hence the good location. The Marriott does not have a Danish feel at all but it is consistent.

Unfortunately the Hotel skpetri is solidly booked for my dates in August. But Wow it looks incredible. Another one I saw was the Hotel d'Angleterre, any feedback on this one?

The Hotel d'Angleterre used to be the undisputed number one hotel for decades. Expect atmosphere, amenities and services of a traditional grand hotel. Good location.

In addition to the Sankt Petri and Hotel D'Angleterre (old school glamour at seriously modern prices) you could also give Hotel Front a try.

Modern with a few interesting touches, views over the Opera if you choose the right room and a restaurant that's great for brunch/light meals.

I second (third?) the motion to avoid the Marriot when there are numerous hotels with a lot more character in Copenhagen .