OH laid underneath his truck to tighten a bolt, while looking up he started to feel dizzy and sick, he stayed there for a few minutes, managed to crawl out still feeling dizzy and sick, managed to get to a garden chair to sit down and gradually started, after a good half an hour, to feel fairly normal again, any ideas please.
Sounds like Vertebrobasilar Insuffuciency, where in certain unusual positions of the neck, particularly if there is any degree of wear and tear in the neck, an artery is temporarily nipped off from the brain causing dizziness and nausea.
No big deal but tell himm to try and avoid theses situations.
Naomi may also be correct that as he is on BP loewring tablets, in the horizontal position hid BP drops a bit too low.
monitor the situation.