Why is the biggest "man" in my life my 4 year old son?

My 4 year old has had gastro for the past 2 nights and I have had the pleasure of changing his bedclothes 876 times, washing 9874 loads of laundry, and soaking various towels covered in the most potently awful combinations of bodily fluids known to man (and child).
While my partner has done some conciliatory “man-upping”, I have still been the one to bear the bulk of the sick child load (as a mum does). So my sleep allotment has dwindled down to about 3 out of the past 76 hours. The night before that, my 2 year old had decided that sleep was so passé and had kept me awake all night, regaling me for hours with scintillating tales of his toe, and kindly reminding me constantly what my name was, just in case I had developed sudden amnesia.
Which brings us to today, Saturday, and I am in dire need of cleaning up my sick hovel. My wonderful MIL came over to help fold the Himalayan mountain range of laundry I have accrued over the past couple of days, but the rest of the house has been neglected owing to needy sick kid.
I asked my partner for help, but when ever I tried to find him to help me with anything, he was either off having a cigarette, having a coffee or listening to the horse racing (in the meantime, I’d re-heated my one cup of coffee 8 times already and didn’t even know it was Derby Day).
I was exhausted, so when he jumped in the shower I told him I was going for a nap. This was fine by him, so I settled into bed and closed my eyes. He then came in, got dressed and announced that he was going to his father’s house (he is his father’s carer and has to go there most days to look after him).
Why did he choose to go right then? Did he think that I could nap while I have one vomiting child and a crazy, not-sick-at-all 2 year old?
So, I got back out of bed, and as he backed down the driveway I exploded into tears.
I heard my sick son call to me then. I went into his room and smiled down at my beautiful, blonde, sunken eyed angel.
While I was unsuccessfully trying to hide my tears he asked, “What’s wrong Mummy?”
“Mummy’s just a bit tired honey, and I’m just trying to clean the house”.
“Don’t worry about me then Mummy. I’ll look after myself, and you just do the cleaning”, he told me through his pale cracked lips.
I hugged him tight before he could see me crying again, and only untangled myself because he needed to be sick again.
My sick, yet still gorgeous, 4 year old was selflessly offering me help.
I stroked his forehead, and told him that he was a beautiful boy with a wonderful soul, and that I would let the entire house rot and go mouldy before I would ever do housework before looking after him.
We then had a little giggle about living in a mouldy rotten house before I left his room and let him sleep again.

This is my boy.

I just know that he will grow up to be a wonderful man.