ah OP, it's such a shame when anxieties about development cloud your enjoyment of your new baby. I was the same with DD; she wasn't smiling at first, and all the other younger NCT babies were, and I stressed a lot!
to take it in turns - I think it's quite normal for them to want to look around. there is a huge window of "normal" for smiling too. and don't expect a big gummy grin, which is what I was looking for - it really is just a curl of the lips at first. when I realised that was a smile, I was all
.
same with the cooing; he's still so tiny. as for toys - you sound exactly like I was. I have so many pics of DD at 11 weeks old, draped in toys or with them pushed into her little fist, and she clearly has NO IDEA what is going on. a lamp is their idea of a good time at 11 weeks. by about 4 months, she was just starting to bat at things over her head on a play gym, but they really don't give a stuff about dolls or teddies etc for ages!
if he is sick a lot, maybe he has a touch of wind or colic or reflux - that would definitely mean he doesn't feel like cooing or smiling much.
some words of wisdom I read on here: he is whoever he is. you can't change that. so enjoy him as he is now, because he will never be this little again. however, if you have concerns, go to the dr and talk about them - if there is something that is troubling him, like tummy ache, they can help you.
lots of luck, it is the most anxiety inducing time, and you're exhausted and your hormones are everywhere, which doesn't help the rational thought process :)