I think Rhys is still very young to be worrying about it. To me it sound like a big developmental milestone that he shouldn't be anywhere near yet (as in another 18 months away). You think what kids draw when they go into primary school, that's only just recognisable. There's so much to learn with colours and objects anyway, nevermind drawing them himself. The only thing we do with Ella is we draw with her, so we draw her a picture to name, colour in or we draw actions and scenes building up so I'll story tell by drawing with her, then something else on a new page (fairly badly scrawled usually and I studied at art school
). She shows a natural inclination to drawing and colouring far more than anything else and is left handed like me, but it's all just scribbles and marks. If she colours she goes straight for facial features to colour in. It's something that family are encouraging too by buying her an easel and aquadraw, so she'll probably get pushed in that direction creatively by intent, though she's naturally interested in making marks. I think if a kid has something like that they love, they will naturally develop their skills themselves.
I'm curious to see what she'll be like as she gets older where both her parent are pretty good at drawing. Like Jan says it's sort of hereditary as well, beyond very basic drafting, but you can't tell until much further down the line really. One of the first things you learn at art school is about colour and how to make marks. Tbh, it's not just about drawing something recognisable or exact, it's more about learning to draw, paint and materials, different colours, tone, texture, interaction, imagination or whatever. There's certainly loads of ways to encourage and develop drawing and painting if it's something he seems to enjoy. You can teach them to draw round and round and turn it into a game by drawing as well with them making different colours, lines and shapes.