It sounds like he will end up with points equivalent to 3 A-levels, so this will likely give him a range of options for uni. It is worth checking the modules on his BTEC against uni entry requirements (look on their actual websites, not just UCAS, as some say they accept BTECs but are a bit fussy about the modules you do!).
If he's good at working independently, and can meet coursework deadlines, then he'll likely be successful on a BTEC. The students who struggle with BTECs are those who leave everything until the last minute, and then rush their assignments, or miss deadlines, so don't get feedback to help them aim for higher marks.
With the BTEC, he will need to hit the ground running, as his first assignments will count towards his final grade, and he may cap himself at a Pass/Merit for some units if he doesn't do well. This means he'll have to work hard whilst some of his friends are still settling into college life.
If he's happy to do this, and the courses meet his interests then that sounds like a great option.
With web design etc, I think for a long time there will be people who want to speak to a human designer, even if AI can do it.