Is it possible that the  number of cases of coronavirus may reach 7.7billion cases all over the world?

That's the entire world population.
I think that in the unlikely event that everyone gets infected at the same time, a lot of people are going to die very quickly because there will be nobody to take care of them. 
That will bring down the caseload rather dramatically.

Yes and the Meek shall inherit the Earth

If no efforts were made to stop the spread of the SARS-CoV-2 virus that is causing Covid-19, then the percent of population having had Covid-19 would, in less than a year, increase to between 50% and 70%.  That would be enough for herd immunity and the virus would quickly disappear after that.  Letting that happen is not an option for Covid-19 due its extremely high rates of hospitalization and death.

No they will not . My FATHER ( GOD) had sent my the cure . I had spreaded to more than 40 countries already , many churches and hospitals around the world . They'll soon stop . If people willing to spread my cure out fast . Less people wil die .