an app to see small lites when charging

You aren't clear. subscribe to what?

I use seeing AI on the light detector function or the app named light detector to see if lights are flashing. The app named light detector has a less annoying sound than Seeing AI. You can’t get colour of LED but you can see if the LED is flashing. If its flashing its charging, if its turned a different colour then its charged. Either way the battery is full so I don’t have any devices where the colour matters. Does this do what you need?

You might be able to get some color detail results from the Seeing AI's scene describer if you take the picture fairly close and cover the camera flash.
It's not clear from the posts whether your hearing aids have two separate lights, green and orange, or some sort of LED that emits either green or orange from the same source. The point being, you could cover the orange one and check the green one with a light detector. I've had to do this with power banks that have the four LED charge indicators. Just uncover them one at a time until it gives a tone change. The drawback is it has to be in a dark place, like under a box, to get a good reading.

Ya, that's horrible. Probably no easy solution either. I remember once suggesting holding a radio tuned to empty AM static near an electronic device to detect if it's drawing current or something like that, but the person didn't have any radios.

Since there are no good ideas, maybe you need to find why you are having issues charging it. Cable? hardware or you!!

So sorry, I should have been more specific. You need to put the phone and thing its looking at in a dark environment.. I use down by the side of the bed if it’s an overcast day or under the duvet if it’s sunny. The camera needs to have a dark environment to show you when something is flashing otherwise it will just give a sound for a lot of light and the tiny light on the thing you’re charging won’t register as an increase. I’ve never found a device with a light dim enough that it wouldn’t register on one of those apps if the surrounding is dark. Your hearing aid may be an exception but I very much doubt it.

One last idea, did you try them against each of the camera modules? I don’t know which phone you have but on my 14 pro max the light sensor app uses the camera module at the bottom of the 3, so the one closest to the lock button.