5 month old dragon doesn't eat

Hey guys, I have 4 bearded dragons (2 adults, 2 babies). I keep them in 4 different tanks (reptisun 10.0 + reptiglo 2.0 with some ceramic heat bulb in each tank of the adults and reptisun 10.0 with regular exoterra heat bulb for the babies). The adults are about 2.5 years old and I haven't had any problems with them yet. Well the problems go now with the babies. There are two, the girl that is huge and the boy that is smaller (not skinny). The baby girl eats a lot (veggies + roaches everyday) but the little boy doesn't. I had problems with him since birth as he wasn't eating so I forced him to eat, putting roaches in his mouth. I spoiled him like this since now kinda. Even though I did the same thing with the girl for about 4 months, she was eating on her own anyway except while shedding. What should I do about the boy to get him eat on his own? Let him starve so he doesn't have any other solution but to hunt?

I wouldn't starve him at that age, especially since his weight is down. It could indicate an underlying issue which could be worse without hydration and some food. Is he alert and active? I would first try some different feeders. Maybe some silk worms if you haven't tried those yet and see if he likes going after something different. What is his weight and length now? If you could post some photos of them it would be helpful.

For the adults I'd also use a bright white basking light. A CHE is good for overnight if needed but they also bask in direct sunlight so you want bright white light, heat, and UVB for all four of them to try and simulate sunlight as closely as possible.

He's not skinny at all, he got his genes from his mom, she's skinnier than the male, and the baby girl got her genes from the male, because she's bigger and spiky.
Yes, he is very alert and active, moving all day, basking etc. I give them all a bath every two days.
The lights in the babies tanks are long tubes so there is a very bright light, in the adults tanks isn't that bright but I'd add some white light bulbs soon.
Here are the babies compared to my hand:
And the adults:

One of the Reptisuns might if it's a T5HO may be the culprit.

See this viewtopic.php?f=6&t=236122&p=1815225#p1815225 , if your local herp club has a UVB meter or even a UVI meter , I'd arrange to have the reptisun 10.0 T5HOs tested , one of them may be a dodgey tube.

There is a natural spread in sizes for healthy well fed hatchling and juvenile central bearded dragons.
This is how my gang grew in their first four months

You can see there is broad spread in bodyweights for healthy baby (5 and 6 week old hatchlings) and 4 month old hatchling/juvenile central bearded dragons.