Maybe talk to your GP without him hearing what your saying, he may suggest he go see someone about him. Your dr might want to give him a physical just to make sure he is ok, sometimes kids can’t tell you.
I think it needs checking out just in case it is more than you think.

He may just be an emotional kid

Not impressed with you referring to him as a cry baby! Hope you don’t say that to his face. Could it be an attention seeking act? Being a twin, maybe he’s looking to branch out on his own

Perhaps you calling him a cry baby could be part of the problem?
It’s totally inappropriate & will damage his self esteem!
There could be many things causing this change in behaviour, feeling left out, feeling his twin is liked more, bullying, it could just be a cry out for attention in general.
Try talking to your son & asking him how he is feeling, why he is feeling that way.
I strongly suggest leaving the name calling out though.
If that stops you may notice an improvement!

It is a cry for attention, try listening to him and what he may be indicating he needs,

Could be just the age thing my 4 year old boy he does that too and i know a couple of his little friends that do the same thing for no reason it’s probably just nothing but all kids are different

he may be a little overwhelmed with things happening in his life
maybe sit down and have a good chat to him and let him know you are there for anything. make sure he knows that you can tell him ANYTHING

I would like a little more info, do they attend daycare? Is he getting bullied in some way?
Is some family member or friend favouring his twin? There are a lot of what if’s. Like the other moms said don’t call him a cry baby and take time out to sit and spend some time with him and ask him if he can tell you what or if anything is bothering him. Best of luck and love to the littlies.

Totally agree with not calling him a cry baby I sure hope you don’t call him that in front of him as it can be damaging for a child. Its always very difficult to cope with a sooky child at any age. But just take a quick mommy moment and try and calmy figure out what the matter is, it can be very difficult but try to be patient with him.

Has anything changed in his routine or life lately? A new sibling? Sounds cynical but maybe the weather? Definitely give him an extra cuddle or two, spend some quality time one on one with him. Love him and see if he tells you whats wrong to make him upset.

Maybe your little boy just needs a bit of a cuddle. Try talking to him. Don’t blame him and definitely do not call him a cry baby.