Fry bacon with oil in a dutch oven over medium heat for about 4 minutes to render fat. Remove bacon pieces, set aside. Add onions and garlic, sauté for about 1 minute over medium high heat. Add collards and sauté for about 2 minutes to wilt greens.
Dissolve sugar into vinegar and broth. Add mixture and reserved bacon pieces to greens. Reduce heat to low and simmer for 60 to 90 minutes until collards are tender. Stir in red pepper flakes. Remove collards and keep warm.
Fry sausage pieces over medium heat in the same dutch oven, just until meat sweats and starts to brown, about 2 minutes. Return greens mixture, stir and heat thoroughly.