Tribunal date approaching, looking for help please

So I was wondering if we could ask the very knowledgable community for some advice as we have our tribunal meeting in a few weeks for our son's DLA.

Previously he was awarded higher rate DLA after our last tribunal meeting some years ago and our reapplication approx 10 months ago was denied.
Our son is now 12 and has CKD and renal hypertension. He is on daily medication for his hypertension and also is prescribed iron and vitamin D supplements by his GP.

We will be approaching our tribunal meeting with a very similar approach as we did last time. However there has been one big change to our son's condition which is reflected in his care needs.
That change is we had to reluctantly take him out of school and home school him to keep him well.

Not long after our son had kidney failure from food poisoning (ecoli 0157 and HUS D+) from a resturant meal in 2008 his growth has been an issue. He has gone from being a healthy baby in the 50th percentile for height and weight to on or below the 2nd centile for weight and about the 10th centile for height.

When he was age 5 - 9 approx at his then school many parents would send their children in with coughs and colds or worse and when our son caught these nasty bugs from the other children he would often develop a fever and then be off his food and become emaciated over a period of days while sick at home.
We are not allowed to give him anti inflamatory medication that is needed for fevers as that could futher damage his kidneys.

Over time / years we saw this turn into a life or death situation after many bouts of this and an emergency ambulance to hospital and a stay of several days in hospital for a fever he probably caught at school.

The good news is in our home school enviroment other home school parents whose children he meets up with are aware of our situation and will tell us if their children are unwell so we can avoid him getting sick as much as we can.

His weight and height has improved slighltly but remain close to the same centile as before. The main things are he is avoiding a huge percentage of nasty bugs which in turn keeps him having a healthy appetite and eating lots of the good food that is good for him. He does love food and a good chicken roast. At home we can give him 3 hot meals a day and monitor his eating which we could not do when he was at school.

His younger brother has also needed to be home schooled because of the above otherwise he would be bringing the bugs back into the house and chances are his older brother would catch it. Our younger son is 7 has no health problems and is approx 75th percentile for height and weight.

My wife had just finished her training as a school teacher but had to give up her plans to teach in a school because she now looks after our children and home schools them. This has had a knock on effect on our income as my wife is a full time career and home school teacher for our two boys.
At the moment we have more money monthly going out than we have coming in and have got into debt and cannot always offer the best home schooling as many of the activities / books etc all cost money.

How do you think we might best present our case and what evidence should we take with us? Have you had to home school your child because of health reasons and what evidence did you take at the tribunal?

I know that since we have home schooled, our unexpected doctors appointments for him have dropped probably around 90 percent or more.
I'm thinking we should approach his GP but unsure if she will or is allowed to write a supporting letter. Maybe we can ask for a print out of his doctors visits before home school and after?
What do you think we should do?

Thank you in advance for any advice or assistance, we spend so much time just keeping him well but not enough time getting knowledge on claiming benifits.

Best Wishes
Peacemaker

If I had one specific question, it would be has anybody here had to home school thier child for health reasons. And if so how did the DWP treat you, did you have to go to a tribunal? How did you get on? And what evidence did you take with you.

It might seem silly but even a little thing might help our son and his case we will be representing soon.

Thanks