Okay, first in the Buddhist teachings you don't have the idea of evil in the Western sense as in inspired by Satan or conspiring against God.
But do have idea of skillful and unskillful action. It's all thought to stem originally from confusion and ignorance - which then gives rise also to anger and inappropriate desires (you do have good desires as well).
So, on the path you try to deal with - first not to be a nuisance in the world - and to deal with confusion as much as you can, and to practise generosity, love, compassion, and to do what you can to deal with the most harmful forms of anger (e.g. killing other humans) and attachment (e.g. sexual misconduct, what that means is society dependent) and so on. Which is then a solid basis for a calmer mind, not thrown around totally by reactions from one thing to the next and able to find a bit of space in your life so you can begin to find your way through to some kind of innate wisdom and understanding we all have in ourselves and natural good sense.
Then, you may have the gradually dawning motivation to help others. Which eventually can become fully fledged so that is your main wish in life, to help others to be free from their suffering and to find lasting happiness, not just the temporary happinesses that fade so quickly - according to whatever is their own individual path and inclination (not that they all should be Buddhists).
This doesn't mean you make no mistakes or are perfect. But when you do make mistakes - still the underlying motivation at this stage is this wish for all beings to be free from suffering and to reach lasting happiness. So, you pick yourself up from your mistakes, you recognize clearly what happened, and the harmful consequences, and then do something to counter it and work towards not doing it again.
So - that's the path of the bodhisattva at that point, and there are many levels, at entry level then you make many mistakes and many things go wrong - but still have this wish underlying.
So - the Dalai Lama - well what he is - depends on what you think. Some think he is a bodhisattva so if he is - would be on that path but doesn't mean he makes no mistakes. Some may think he is actually Buddha - that is also possible - then he may be doing things that look like mistakes to us because the only way you can interact with beings like us is in imperfect situations with imperfect bodies. Or perhaps he is just an ordinary Buddhist monk, keeping his vows as best he can, and occasionally making mistakes, and also doing his best for Tibet because of his unusual situation.
There are many possibilities there and you don't have the idea of a canonical saint as in the Catholic Church. So different people will see him (and others) in different ways.
But you don't really have this idea of evil as such in Buddhism. Even someone who does something really extreme and terrible like a mass murderer or torturer or someone who engages in "ethnic cleansing" of entire populations - terrible though that is - is not thought of as inspired by Satan.
Rather, they are confused people overtaken by harmful thoughts and ideas and emotions, maybe extreme anger - and maybe crazy obsessive thoughts that take over their entire lives and cause them to harm thousands of others - but underlying that, is still all resulting just from confusion and ignorance and not really understanding themselves or the world very well. True wisdom and understanding can counter that if they could only access it. Are stories e.g. Buddha's life story one of his followers during his life was a mass murderer who killed dozens of people before he met the Buddha.
To the ordinary Tibetan as I understand it, the Dalai Lama wouldn't be thought as perfect like he never makes a mistake.
It's rather, that they greatly respect him, and they consider that it's a blessing to listen to him teach or just to meet him.
They also feel that in some way there's something in him that can be transmitted to others. Ordinary Tibetans believe he has a special connection with compassion, as I understand it, so by meeting him you also make this connection yourself.
But, it's not like that the Dalai Lama's compassion differs from other people's compassion. If anyone does something very compassionate, then a Tibetan will say that they are the embodiment of Chenresiz, just as they say about the Dalai Lama - that just means that they have shown compassion in this action.
Everyone has this same capacity for compassion, according to the Buddha's teachings. Also wisdom as well. But as I understand it, the Dalai Lama is especially associated with Compassion according to tradition in Tibet, and by meeting him you can make this same connection, to your own unbounded compassion you have in yourself.
It's like in some way pointing out this possibility for compassion which was hidden, that some kind of direct connection can be made. And what matters is whether he is able to do that, help you make this connection to compassion - and not particularly what his actual personal practise is like, that's almost irrelevant for the process.
So many Tibetans believe he can. If you don't then that's fine, is not a problem if one thinks that when you meet the Dalai Lama that it is nothing special at all.
It's the student that matters here much more than the teacher, and indeed it's possible to get that transmission of compassion from anyone - no need at all to be the Dalai Lama - and could be even from animals and birds some of the stories.
For a bit more clarification - it depends much more on your connection and is not like an absolute intrinsic thing in others (except in the sense that we all have this capacity for unbounded compassion), and they may not know that they are making htis connection for you, often won't, and might often not be people you'd ordinarily think of as particularly compassionate, and perhaps sometimes wouldn't think of themselves that way either - or is just an animal or a bird, doesn't even think that way at all - or even inanimate things like a cloud, a pattern in a cloud, or a waterfall or some such.