I think he can if he is double jabbed as those restrictions end on the 16th. That's assuming he doesn't go on to develop Covid in the meantime.
I thought it was if you were pinged after the 16th you don't if double jabbed but if you are pinged before you still have to do the full 10 days no matter what.
I don't think so. I had a quick google and the first result was an article in the Independent containing this paragraph:
'But the new rules confirm that if a person’s self-isolation period began before 16 August and was due to end after 16 August, they will be able to leave self-isolation on 16 August. People who have tested positive for Covid-19 will need to continue to isolate for a total of 10 days.'