Major Sleep Issues

Hello ~ we rescued a PWD 8 months ago. He was 8 months when we got him. We are currently having some major sleep issues. He sleeps in a bedroom (not ours, one with no humans) in a crate with his 3 yo boxer sister in the room who is in a separate crate. He pretty routinely falls asleep on our LR floor around 8:45-9:00 and then we do one last trip outside around 930 and then goes up, into crate for bed with zero problems. Recently, he has been waking up several times a night starting around 1am (like 3 or 4 times) and crying/barking his head off for long periods of time and no one in the house is getting any sleep at all. He is very vocal and very pitchy so it's driving many of my family members insane and we are all exhausted. Before this happened, he was sleeping through the night, no problems - although he always got up hella early, like 5:45am- 6am but I attributed that to he fell asleep pretty early. Right before this started happening (around 2 weeks ago) the boxer had some GI stuff and I had them both in bed with me so I could keep an eye on her and let her out and clean up, etc. and now I feel like he is so off track. The other "event" that happened was that the PWD had been getting up super early, like 430 and my husband has a very stressful job so I would get up, let them out and then go back to bed in a different bed for a little bit with them. That was probably for about a week before the boxer's issues.

I thought maybe in a day or two of letting him cry it out, etc he'd understand I'm not coming but so far no luck. There have been some nights where he has slept right through, but we are honestly probably at about 60/40 on that, not in our favor. A couple of other things about him and us:

--We love our dogs, this one included. We had another boxer we just lost this past year at about 10 years old, so we are not new dog owners.

--We don't want to sleep with the dogs in our bed. I know some people feel strongly about this but so do we. This wasn't an issue before the female boxer got sick.

--Both dogs are in their crates during the day when we are out, pretty much with no problem. The PWD has started giving me a little bit of business, infrequently, getting into his crate, but for the most part this has not been an issue at all. Ninety-five percent of the time he walks happily in, just like he does at night. I can leave them in their crates for about 4 hours at a time if I'm out during the day. The PWD starts to get antsy after that ( I have a nanny cam)

--They get plenty of exercise. We have a big yard they play and run around in. They love to wrestle and play together. I walk them twice a day, somewhere around 4 miles total. He in particular, has a ton of energy and does have difficulty finding his "off" button sometimes. He is 16 months.

-- I do some training with them, place, come etc, basic commands but I don't do any scent work (basically, I'm not exactly even sure what to do) Could this help? Should I be doing mental games before bed?

-- He used to demand bark A LOT when we first got him. That is almost completely eradicated. He will still do it to his boxer sister when he wants to play.

--I realize that going back to bed with him, her getting sick probably created or added to these issues. I would love some advice from anyone who has had similar experience and has gotten past it. Last night I took the advice of someone on Reddit who put an alarm clock in their dog's room as a way of indicating that when the alarm goes off is when you will see Mom and Dad. This was the first morning of that.

Thank you if you are still reading this and happy holidays. May they be rest-filled ; )