First, Jehovah's Witnesses [JWs] do not believe the world will ever end. They expect the battle of Armageddon but that obedient ones will survive and live during a one-thousand-year reign of Christ over the earth, which will become a paradise and last forever. When JWs speak of 'the end' they mean the end of the present wicked system that will be destroyed at Armageddon. They never mean 'the end of the world'.
Second, the accepted answer is correct in simply stating that no statement about stopping worldwide, public preaching has ever been made. Your friend is mistaken, indeed. However, he is not delusional for there have been some statements made to JWs over a period of years (recently), and there are also written indications that a time will yet come when JWs will need to stop public preaching.
The 2014 book published by the Watchtower Society (quoted below) shows why your friend might have jumped to the conclusion that, at the beginning of the Covid-19 lockdown, their preaching work was then permanently finished:
"9 This will not be the time to preach the 'good news of the
Kingdom'. That time will have passed. The time for 'the end' will have
come! (Matt.24:14) No doubt God's people will proclaim a hard-hitting
judgment message." (God's Kingdom Rules! chapter 21 pp220-230 for
the full section.)
Your friend may also have seen videos shown to JWs at their summer conventions (in 2017 and prior to Covid-19) which dealt with JWs going door to door to give a warning message only (as the quote from their book stated.) One link is https://www.youtube.com/watch?v=z3TipJ_x6yg but because I currently won't agree to You Tube's terms, I cannot see anything they put up so I cannot confirm this 4-year-old link. However, it had the title, "The end is near for door to door preaching". Your friend might have noticed that.
In that 15-minute video, the only part relevant to your question was what a former JW found out from her aging JW mother. She said that the following year, in 2018, the JWs would be told that they would only go from door to door to give a warning - that Armageddon would be upon the world. JWs were told to have a three-day supply of food and water ready, then wait to be told from their leaders their instructions.
In light of the 2020 Covid-19 pandemic, that may well be viewed by JWs as confirmation that although they will receive preaching via Zoom (which non-JWs can also join, I think) their public door-to-door preaching is being wound up. Now they write letters and make phone calls, or e-mail people whose e-mail addresses they know. In that sense, they still continue their ministry, but so far no door-to-door work has resumed.
This is just to flesh out the bare bones of the correct, accepted answer, to add that although your friend was mistaken, he could also have read such bits in that book and saw JW-produced videos at their summer assemblies before Covid-19 struck. Even then, they were being encouraged to have "Go-Bags" ready, in anticipation of the Great Tribulation suddenly starting, and needing to hide away from public scrutiny, as much as possible, trusting that their obedience to instructions from their leaders would then give them Jehovah's protection.