Deryck Whibley has detailed his recovery.
The musician was discharged after responding well to treatment.
The group will officially part ways after they release their final album, Heaven :x: Hell, later this year.
The Complicated hitmaker took to Instagram on Thursday to share that the singer/rapper proposed to her in front of the Eiffel Tower in Paris, France on 27 March.
The stars enjoyed a meal in West Hollywood over the weekend