Why we have to elect somebody like Donald Trump

One of my friends (A) have expressed in a discussion with me his dislike of Donald Trump. I (B) responded by making the point that we may dislike Trump but, to save our country as we know it, we have to elect in 2016 him or somebody like him to be our President. Here are some points of this discussion.
(A): Are you taking Trump seriously among other Republican contenders?
(B): Yes, I am taking him seriously but with a deep anxiety. If any other Republican contender becomes a president, many things will be much better as compared to what we have now and what we may expect from Hilary Clinton who would essentially continue the Obama policies. However, it would be not enough to reverse the country’s decline – the decline will continue although at a slower pace. With Trump, there is a chance to reverse the trend and restore the nation’s greatness, although the risk is great.
(A): Well, if he is nominated, Hillary will have a much better chance to become president. The other problem is Trump is just as inexperienced as Obama was in 2008 and just as narcissistic. Bad combination, in my opinion.
(B): You are right but that is the risk worthwhile to take. All “experienced politicians” who pretend to be “ordinary citizens” have put the country on the way to spiritual and economic decline - that is what we have to remember while choosing whom to vote for.
(A): Trump is surging because "the elites" of both parties have failed miserably in the last 15 years or more, and Obama turned out to be simply anti-American (as most Americans understand it). However, from what I have heard from Trump, I think he has not ideas but good-sounding slogans that are either very difficult or impossible to implement in real life. So if he is elected, I am afraid what will follow is not some renewal of America, but just more chaos. Put another way, I have learned not to trust in a "knight on a white horse". More likely, though, I think his nomination would rather pave the way for the Clintons and Democrats to remain in power, and that would not be fun.
(B): My assessment of the situation is different. “The elites” as you called them are experienced only in inventing new goodies for the potential electorate to be elected and then do the wealth redistribution from us to them. The Republican “elites” sound much better to our ears but the result is the same and the result is very destructive. I do not believe that the victory of the establishment “experienced” Republicans would create the change we desperately need. In addition to the Republican victory, we need something else. We need somebody to create first a sort of anti-establishment revolution and then somebody else who may create something fresh and new. Trump is a possible candidate for this job – of course, with all risks involved. His business experience for American restoration might be more valuable than the experience of all “experienced politicians” running for the president. Why? Since we do not need more new government programs that all “experienced politicians” are creating – we need good management including a sharp reduction of the ineffective 2/3 of the government, and nothing else. And Trump has the best experience among all of the contenders to do this – to do just “good management”.
(A): The late principled conservative William Buckley once said that a voter must vote for the most conservative candidate who can still be elected. Ronald Reagan was an experienced politician before he became president. In the post WWII USA, there was no president who came to the office without professional political/government background.
(B): We have had conservative Presidents and Congress elected as Conservatives such as Reagan, Bush H., Bush W. However, the march to abyss has not stopped – the taxation is growing under various concealments, the nation’s debt is mounting, the government “free stuff” is rising, the government regulations of individual citizens are increasing, the individual freedoms are shrinking under the pretense of democracy.
Thus, just a conservative government, even following the advice of the great William Buckley, is not enough to stop the march to abyss – we have to change the political thinking, a sort of way of spiritual thinking in this country, in addition to a conservative government, if we are to begin the restoration.
The existing ruling news media and the both-parties establishment have created the current political politically-correct thinking. Therefore, first, we have to dethrone the news media and the establishment, and Donald Trump is the only candidate who is doing it successfully – nobody else. However, all your risk-related points with the Trump’s candidacy are valid. 
In conclusion, an almost quote from a popular news media outlet:
Trump is popular and it is undeniable. It is because people are afraid, and Trump is pushing the fear. The Trump is telling the people they should be afraid of Muslims, of Mexican immigrants, of China's business practices, of President Obama, of Black Lives Matter, of stricter gun laws, of ISIS … However, all those threats are the Trump’s conspiracy to scare the electorate and win the election. Do not trust Trump – trust us the news media and the political establishment we are representing.
The problem is the threats Donald Trump is describing are real and supported by the facts, and the people feel all that. This popular news media, as many others, is deceiving the people by denying the existence of those threats, and it is doing all that to continue profiting from a politically correct march to the abyss.