S.A.
Congratulations on the great husband and father that helps at home. Wow!!! (just a little jealous)
Anyway, the only thing I could suggest would be to make them go back and lay down. Don't ask, don't beg, don't request it...when they wake up at 6:30 tell them it is not time to be awake and they will lay back down until mommy comes and gets them. Period.
My little one started wanting to get up around 6 am for awhile and when she did I marched her little self right back to her room and explained that mommy was tired, it was not time to be awake....even Mr Sunshine was still sleeping...so she had to lay back down. Period.
Maybe my girls are just easy but I don't give them an option and it has worked for me.
Good luck!!! Sleep is such a wonderful thing.