A devastated Antoine captioned the video and pictures "you never emerged from the depths, so you never got to hear my answer, yes! Yes, a million yes I will marry you.
"We never got to embrace and celebrate the beginning of the rest of our lives together as the best day of our lives turned out to be the worst."
According to Associated Press, Weber's sister Mandy Hoffman broke her silence on Tuesday, saying the whole family was still struggling to understand how Steven died.
According to Hoffman, her brother was a strong and experienced swimmer.
"This is all we keep talking about. Something else happened besides him running out of breath."
Hoffman told the publication that her brother wanted the proposal to be a special one for Antoine.
The CEO of the resort, Matthew Saus, conveyed his condolences to the families and friends of Weber. "Our sincerest condolences, thoughts and prayers are with his girlfriend, families and friends impacted by this tragic accident."