The windows I have in my house are insulated (but these windows have very low R-values in and of themselves). The main function of the gas in mine is to filter out UV rays. When mine were repaired the guy that came out needed to remove the window from the frame take it out to his truck, install the new panes and flush them with the new gas.
Do you have any warranty info on the windows? Mine were installed in 1996 and I thought for sure they wouldn't honor it this year as the windows were cracked. They did, and I have two brand new windows. If I futzed around with them myself, I would have voided any warranty. If you have the information, call the contractor that installed them. It's worth a shot. I would think that if you did the work yourself, any moisture in the air between the panes would get trapped once caulked and would continue to condense.
Just some thoughts, if getting replacements is out of the equation right now, you could do what your friend suggests, but some windows aren't easy to remove without special tools and skill. I would have been able to replace mine at no charge (if I just picked up the new panes), but I wouldn't have been able to flush the gas. I also looked at the instructions for doing the replacement and figured I'd crack the glass and be up the proverbial creek. I'm used to replacing double hungs, so this wasn't going to be the same.
These are my ramblings. Maybe someone else can chime in.