They weren't close at all. They didn't have an atomic bomb development program. They had an exploratory program looking into whether it was feasible, they concluded it wasn't likely to be important in the present war, and they focused on developing nuclear reactors instead. They almost had a small, experimental nuclear reactor working by the end of the war. Which is to say, in the spring of 1945 the Germans were almost to the stage the US had got to by winter 1942.

Not at all, their resources was very limited and most of their scientists defected to the United States in fear of being persecuted for opposing Nazi rule. Also, most of their resources were widely destroyed and/or disrupted by Allied round the clock bombing raids on their cities so the Germans had a very hard time getting access to ingredients to develop nuclear weapons successfully.

Germany did have a number of genius scientists working on the German atomic weapon project - Otto Hahn and Werner von Heisenberg among them. However, many German physicists left the country before the war for political reasons (many were Jewish and/or socialists), while many other physicists were drafted into the Army to fight (and die), and many others were assigned to what was perceived as more important research.

At the same time, the German atomic weapon project did not have strong government support - while Churchill and Roosevelt were both very supportive of Tube Alloys and the Manhattan Project, Hitler was more focused on bigger and better planes, tanks, guns, and rockets. There are a number of reasons for this - Hitler may not have had quality science advisers (the Nazi Party was notoriously anti-science, particularly nuclear physics, as it was perceived as having been "tainted" by Jews) and was more impressed by weapons he could easily understand that looked impressive (hence his support for such useless programs as super-heavy tanks).

This lack of support meant that the German program did not receive the resources it needed. The Manhattan Project eventually employed over 200,000 people and cost almost $2 billion - that's as large an investment as the United States made on small arms (pistols, rifles, shotguns, and submachine guns) for its very large military. Germany didn't have the resources to spare for that kind of investment on a project that might not even have worked or been ready in time (the US only developed the weapon after Germany was defeated), and that would have taken resources away from more important projects, like weapons for the infantry or more tanks. More support for German atomic bombs means fewer tanks to fight the Russians with.

The German project was also totally mismanaged - there was no centralized direction, but instead many little projects all working on their own thing but never working towards the same goal. Imagine if an airplane design team had each team all building what they wanted, but in the end they wound up with a stealth airframe using a propeller engine with a catapult that flung rocks on top. That's an exaggeration, but the German project wasn't too much better.

Finally, while many of the German scientists were brilliant, they continued to believe that their reactors would need heavy water (which was produced in Norway and was thus vulnerable to Allied sabotage), and they never did realize that they could use carbon for their reactor's moderator instead. Thus, they were using a much more vulnerable source that was much less efficient and far more expensive.

So, they didn't have enough scientists, technicians, money, or the government support to acquire these, and they were going down the wrong research path in a muddled direction.