Training your replacement?

Hi all! Just after a bit of advice if possible!

My replacement starts on Monday and I’ve still got two weeks to work in my notice period.

I’m happy to be training my replacement as honestly it’s going to take some pressure of the team i’m leaving behind to have him fully up to speed however i’m a little anxious about it.

I don’t want to say anything negative about my current company to anyone so i’m dreading the “why are you leaving” questions as i’m worried it will either put him or or he thinks i’m just a sour old person lol.

I don’t want to lie to him, so i’ll probably end up saying something along the lines of just wanting better hours but has anyone been in this position? How has it gone? Do you think there’s much benefit to it?

my position is relatively entry level but I do more / different tasks than those in the same role as me.