You have a leak in the double panes seal someplace. To stop the condensation you can either take it to a shop that can repair it (pricey), replace it (pricey) or do it yourself, which may or may not solve the condensation problem. We used to know a guy in NC that would custom build a double pane window to match original vintage windows. He and David were talking about it one day before he started doing them. I don't know how long they last or what but this is the method David and the guy came up with.....
Basically it's a piece of plastic or metal framing. A heavy bead of butyl (in the tube not the rope) is laid down. A VERY clean piece of glass is next and embedded into the butyl. This is let dry. A 1/8 to 1/4" spacer is laid on top of the glass and sealed in. Let dry. Then the fun part. Using a high temp heater (I think they decided on a construction Ready Heater). The glass is heated until hot and the top piece of glass is quickly sealed into place on top of the spacers. All the glass has to be very clean as yio can never clean the interior of the glass without tearing it apart. The basic principle is like canning food in jars. The heat expands/exhausts the air and as it cools a vacuum is formed.
This is a lengthy thread on fogged windows. On page 2 some guy (d.a.n.) drilled a couple tiny holes in his windows and the fog dried out in a few days. I think if you did similar (but drilled thru the metal encasing frame not the actual glass) and then let it dry and (on a hot sunny day) leave the glass sitting out to heat up and seal the holes up, that could solve the problem. At worse, you would have to buy new ones which you may anyway.
The deal is, I think dual pane glass is over hyped and over rated. Regular single pane glass is R-1, dual pane is R-2. If it is filled with a gas that will bump it up a percentage of the R-2. BUT, and this is the big one, the FRAMING that the glass sits in is usually not included in the R-Value ratings. Any metal will act as a heat sink and guess what the glass is framed with in an RV???? A layer of Reflectix over single pane (that will cover the metal frame as well) will increase the R-value far more than dual pane and far cheaper. Can't stand living in a "cave"? Then use clear bubble wrap like what is used in packing breakable items. You can buy that by the roll in many places. Can't remember where I found it (alternative energy website) but the clear bubble wrap dropped the temp loss on a single pane window almost the same as the Reflectix.