Most kids are abit teary/clingy when they have to go to nursery as it's such a big adjustment and he may-be feels abit jealous if he knows his sibling is at home enjoying mummy. Have you spoken to his teacher about how he is in the class once you have left him? If she say's he is fine then I would just start taking him again as he will have to go when he's 5. He will soon make friends and then you may find that he will want to go and play, plus it is vital for their development to interact in the school environment. Don't forget kids are very good at manipulating parents emotions and although they may-be very young they do know what they are doing when they behave like this and if he know that when I scream and cry them mummy will take me home and I don't have to go to school. Be strong it will be worth it for him in the long run. xx
What does he say he didn't like about the nursery?
Do you have a sports centre nearby where you could leave him in the creche for an hour or so at a time, this may give you an idea as to whether it is the separation he dislikes, or just that particular nursery that you put him in.
If he gets on OK at the creche, maybe you could then look for an alternative nursery for him.
In my opinion, the more sessions they do, the quicker they settle and make friends.