Really sorry to hear your friend is so unwell. It must be worrying for you and for him.
To give context to my comments, I was a Speech & Language Therapist in a hospital. In that setting my job was mostly working with people with swallowing disorders, so I was involved in the decision-making process for whether people needed a feeding tube, alongside dieticians and doctors. The people I worked with had conditions like stroke, dementia, Parkinson’s, motor neuron disease, chronic obstructive pulmonary disease etc.
I am not a doctor, and I was never involved in a case of a person with ME/CFS. I’m just familiar with some of the considerations involved more generally. My suggestions are about information you can gather that would be helpful for the dietitian and doctor.
If you can find a local dietitian/doctor familiar with very severe ME or recommended by someone with or the carer of someone with very severe ME who has had a lot of trouble with eating/drinking or needed a feeding tube, use them.
A BMI of 18.5 is a normal BMI in the UK and US; it is the lower bound of the normal range. So that by itself is unlikely to cause concern to doctors.
In terms of weight, what matters more to the dietitians and doctors is whether your friend is losing weight over time, when he’s not trying to. If your friend has a record of his weight in previous years or months, and there is a clear pattern of weight loss, then it would be helpful to show this to the doctor.
If he doesn’t have a record like this, it might be helpful to start keeping one now.
Your friend/a carer could also keep a record of everything your friend eats and drinks each day for at least a week – including the amounts, e.g. two tablespoons porridge, three sips apple juice etc. This will allow the doctors and dietitian to see at a glance how much food your friend is managing to take in, and whether your friend is getting enough nutrients to keep his body working as well as possible.
Also record why your friend is not able to eat and drink more – e.g. is he not able to chew the food? Not able to swallow it so it just sits in his mouth? Or does he get nauseous or vomit if he eats more? Or does eating take so much out of him that it makes his ME symptoms much worse?
I’d think of it as – your/your friend’s/your friend’s carer’s job is to show the doctor or dietitian
(a) what your friend is able to eat and drink each day, and how long this has gone on for
(b) whether your friend has lost weight when he didn’t mean to, how much weight he has lost and over what period of time
(c) why your friend is not able to eat and drink more
The doctor and dietitian’s jobs are then to figure out how to optimise his nutrition, whether your friend would benefit from a feeding tube, and if so, which type.
Dietitians are key in helping people who are unable to eat/drink enough and establishing if/when and what type of feeding tube will help. If your friend hasn’t been assessed by a registered dietitian, see if he can be.
Ask for what you need. If the best way of assessing him would be for your friend’s main carer to send the dietitian more information on the problem by post (e.g. food diary, details of weight changes etc), followed by a video/phone call between the dietitian and your friend’s main carer, then ask for that.
Nutritionists are not the same as dietitians and it’s a dietitian you need. If in the UK:
https://www.nhs.uk/common-health-qu...-find-a-registered-dietitian-or-nutritionist/
In general, feeding tubes will only be considered if adequate nutrition cannot be given orally. There are risks with all feeding tubes, so this is sensible. Sometimes high-calorie foods/supplements and changes in timing and size of meals will be enough, and the person won’t need a tube.
The person also needs to be able to digest the food, i.e. things need to be working below where the tube goes in. So if a tube is going into the stomach, then the stomach and bowels need to be working reasonably well.
If your friend needs a feeding tube, there’s no way of knowing which tube will be best without a lot of medical information about his specific case. The dietitian and doctor will have/get this information. The type of tube I’ve heard people with ME using most is this one. A PEG tube is used when someone is going to need tube feeding for an extended time, and their stomach and bowels are working reasonably well. A little tube goes from the outside of the person’s tummy straight into the stomach. It’s closed off with a cap when not feeding. When feeding, you attach a bag of feed (a bit like a drip, where the bag of liquid hangs up high and attaches via a thin tube to the person). The PEG tube requires a little operation or procedure to put it in, but is then managed at home. If your friend is completely bedbound then his carers would be trained to maintain the PEG.
Here’s more on PEG from an American source, but remember, this might not be what your friend needs at all.
https://gi.org/topics/percutaneous-endoscopic-gastrostomy-peg/
I really hope this is helpful. I won’t be able to post again, as I have severe (not very severe) ME.
Try local and national ME associations for more information, but bear in mind that your friend’s case will not necessarily be the same as other people’s. A good dietitian will be really helpful.
@Peter Trewhitt has made a lot of good points above.
Wishing you and your friend the very best.