I am glad the posts on here from everyone have been helpful. I am more than happy to help.
Sadly, there are still medical professionals in this country who give inappropriate advice as they have not been taught the correct information about post viral syndromes or ME - even implying the parent is mollycoddling the child, as you felt the nurse might have felt - and giving harmful advice to push through. Your son might be able to do some exercise within his energy limits, so the nurse saying if he feels up to it then let him do it is in itself not wrong. The key is working out what his energy limits are, how to spend his energy and not to push through.
This is why a diagnosis is important if that is what the person has and exhibits all symptoms getting worse after exceeding their individual exertion limits. Pushing through if they are like this risks further deterioration in functioning and impedes improvement. At the worst end of the scale is a child or adult being put on an inappropriate graded exercise therapy programme and going from mild to severely affected.
In the video I posted of the 2 doctors, Diagnosis of paediatric ME/CFS with Dr Nigel Speight and Prof Peter Rowe, you will see they cover, starting at 8 mins, 30 seconds, how sadly ME (should that be what your son has, it’s a specific constellation of symptoms) has been controversial, especially in the U.K., US has been a bit better in recent years. The controversy is the false claim - and the dominant one for many years and still prevalent in this country amongst the medical profession - ME is either fully psychological or has a large psychological component. As Dr Speight says in the video there have been 3 major reports that make it clear ME is a physical, organic condition. The US 2015 Institute of Medicine (now known as the National Academics of Engineering and Science) report states:
“It is clear from the evidence compiled by the committee that ME/CFS is a serious, chronic, complex, multisystem disease that frequently and dramatically limits the activities of affected patients.” www.ncbi.nlm.nih.gov/pubmed/25695122
The U.K. NICE guidelines are currently being updated, link here. www.nice.org.uk/guidance/gid-ng10091/documents/draft-guideline
The new draft guidelines say it is a complex, chronic medical condition affecting multiple body systems. It also says it should be recognised tthat people with ME/CFS may have experienced prejudice and disbelief and feel stigmatised by people who do not understand their illness. It also says, ‘be aware of the impact on children and young people with ME/CFS who have experienced prejudice and disbelief by people they know and who do not understand the illness (family, friends, health and social care professionals and teachers). Health and social care professionals should understand this experience may result in a breakdown of the therapeutic relationship, lack of trust and hesitation to engage further in health and social care services.’
As said, it may well be may well be your son will not develop full blown ME, but has a form of post viral fatigue syndrome. However, the management principles, pacing etc, for post viral fatigue syndrome are the same as ME and if applied reduce the chance of it developing into ME. All the best to you and your son, feel free to ask me further questions anytime.