Ds doesn't understand about death or anything he's quite far off that level really. Sorry no useful advice open, but if he's seen it on tv programmes and as you say about your neighbour, maybe that's why he's becoming inquisitive? But yes it is a completely normal phase. How did school go today?
I tell ds you can only do certain things when your an adult, such as drive a car, drink beer etc. I said to him tonight, come on let mummy brush your teeth let's clean them 'adult teeth', so he looked at me really buzzing and said ds is an adult now, ds can drive mums car and ds can drink beer. In your dreams pal haha. I do think he actually thinks he's an adult now and can do those things, I have to be careful how I word things, should be interesting when I take him to the car for school tomorrow morning and he thinks he's jumping in my seat 
Hope ds nursery visits go well light.
We had an epic meltdown this morning, over an electric toothbrush, my mum was here and we were both thoroughly exhausted by the time it had finished, worst one he's had yet.
He's asleep now, all school uniform ironed, bags packed and I'm really looking forwards to a few hours respite tomorrow I'm not going to lie!
Hope school goes well for everyone this week x