I'm sorry to hear that Trouble is meowing more often and choosing to do so at 4am, but he's certainly gotten your attention hasn't he?
Cats that are suddenly even more vocal are trying to tell us something, but unfortunately there are many problems that can cause yelling so it takes some detective work to figure out exactly what the problem (or problems) is (are). He is comforted getting his "needs met" and being distracted, so my hope is that the problem may be in its early stages, but I do recommend looking for a cause.
Ideally he would have a physical examination but even if his physical examination is within normal limits, further diagnostic tests to find the cause may be needed.
I would start with a complete blood count, biochemistry profile and T-4 and a urinalysis.
Hyperthyroidism or an overactive thyroid gland is usually caused by a thyroid gland tumor. It can put cats on edge as they are overstimulated and can make them hungrier as well as it causes a ramped up metabolism where they burn more calories. Both of these things can lead to yowling. This can be diagnosed with a blood test.
His kidney disease may be worsening and causing secondary hypertension (high blood pressure) which we believe may cause headaches. Blood pressure in cats tends to be higher at night when they are more active, so it would make sense that's when he feels things most.
A sore tooth, gum infections or a mass on the tongue or tonsils can lead to mouth pain and could be the cause of his yelling. He may be distracted during the day and only really become aware at night when all is quiet. He may need sedation by his veterinarian to fully examine his teeth, tonsils and tongue and diagnose these conditions but it won't hurt for you to take a look if he will let you.
Senility or dementia often causes cats to vocalize more. They are literally yelling because they are lost and confused and are calling for help. This is usually a diagnosis of exclusion meaning that physically everything looks and tests out normal but they are still vocalizing.
His sight may not be what it once was so leaving on night-lights to help him see may help and feel less anxious.
As animals age they sleep less soundly. It may help to play with him more during the day/evening so he is tired at bedtime and sleeps better. In some cases using music or "white noise" machines to block outside noise is helpful.
If his days and nights seem a bit mixed up it may help to give him a supplement called Melatonin. This is a naturally found hormone in animals and people that helps regulate the sleep/wake cycle and is involved in seasonal shedding. It can help them relax and sleep, and in cases that have abnormal shedding patterns related to seasonal light changes or abnormal growth hormone fluctuations. The usual dose in cats is 2mg to 4mg per cat every 12 to 24 hours. Make sure to give a dose 2 hours before bedtime.
Make sure to read the label and DO NOT use the fast dissolve tablets of Melatonin with xylitol as xylitol is toxic for cats.
We can use calming sprays or diffusors containing Feliway, a homeopathic drop added to his food or water called Rescue Remedy, or a supplement called Zylkene.
Drugs such as Anipryl (selegilene) can help with brain function. If that isn't enough then your veterinarian may prescribe a low dose calming medication like alprazolam.
In short it sounds like your fellow needs a physical examination and minimally some blood tests taken to look for reasons for his "talking". If there isn't a physical cause then we can proceed with altering his environment and using things to reduce anxiety.
Please let me know if you have any questions.