You seem like a good guy and I don't want to be a dick to you. I do think you're missing two key points:
1) This separation is nothing new. It happened under President Obama. It happened under President George W. Bush. Check the photos online of Obama-era detention facilities for kids. Anytime a parent is prosecuted for improper entry or illegal re-entry, the kids are sent to a detention facility. That's the system we have. You say it's "not a good look for the US", but was it a good look in 2014? The difference is the media hates Trump and is twisting every story in an anti-Trump direction.
In terms of caring for the kids while their parents are being prosecuted---more funding for better detention facilities would do the trick. But that would require Congress to approve the funds.
2) Trump is not the king. He can't change the immigration system without Congress.
I also don't know from where you're getting the idea that Trump wants to separate kids from their parents. He says he doesn't want to. You might respond: I know from his actions! But then, Obama did the same thing. It's the system we have. I think it's important for us to be constructive rather than destructive. If there are problems with the current system, let's discuss them and push for those fixes to be implemented.
Even if we build the wall and go after employers hard, some people will make it across with kids. What should happen then? In my ideal world, the parents would get a court date within three days of being apprehended, receive their sanction, then be sent to DHS to be repatriated to their home countries. Meanwhile, the kids would stay in grade-A facilities until their parents are processed. That's the humane way to do it. Trump and Sessions have already taken a big step in that direction by sending more prosecutors and judges to the immigration courts, but the real fix must come from Congress.
By the way, I never claimed the holding facility was "not a cage", so I don't know where you are getting that from.