How do you deal with a primary school student?

I'm now, so to speak, tutor of a primary school student who comes from the 3rd in the 4th grade. He has a reading and writing weakness. I have to learn vocabulary with him in English and probably also a bit of grammar. In German the lettering and dictations. How can I talk to him, because elementary school students are somehow too old for "that's what you did great" or "imagine this is a unicorn" haha I think you know what I want to say, somehow I can't think of any better examples. But they are too young for "Now working on this continuing task" So I wanted to ask how I could talk to him, he is very excited and likes Minecraft. In addition, I would like to know how to improve the readability of the lettering with a primary school student and how I can learn with him words, so what I have listed above.

A simple well done or very good is enough. You can't force it, but the best way to improve it is to write down the alphabet over and over again. Alternatively, pay attention to certain letters which are not legible and point out. When introducing vocabulary vllt introduce reward system or so 🤷♀️

Thank you for your answer, but how exactly do you mean that with the reward system?

Was just an idea, but does not make so much sense because you want to make money yourself instead of spending something 😅

Is still a good idea. It is also used in many primary schools under the name amplifier plan to reward positive behavior (in this case learn vocabulary). Mostly it's about "good" behavior to "collect" something (smileys, stars, points…). From a certain number there will be a previously agreed reward, but this can also come from the parents! (Eat an ice cream, stay longer or something similar). If the parents are on board, that would be possible.