I'm in Wales so the grades and options are a bit different, but if by passes in English and maths you mean the equivalent of old Cs, that's a huge help as those are the ones employers and colleges are most interested in. He should definitely be able to get onto level 2 courses at an Fe college, and maybe even some level 3s might consider him (not Alevels though). Many many people will have much worse grades than that.
In our area there are very few opportunities for GCSE resits apart from maths and English, unless you pay for online courses / sitting as an external candidate, but plenty of Ievel 2 btec equivalents. Btecs may suit him better if it's the exams that seem to be the problem, rather than his school work in general.
Try not to focus too much on GCSEs / Alevels being the 'normal route'. It's not for a lot of people, and I've seen many people turn down courses they could enjoy, or be good at because 'gcses and a levels are better ' or 'i don't want to be behind my friends ', when in fact their GCSE results show they need a different route. And those messages are usually from parents, so be careful how you talk about the courses.
It's also worth him reflecting on what 'went wrong' to learn from it for next year, if he was predicted higher. Did he put in as much effort as he could, both in and out of school? Or does he just not perform well in exams? Or did something go wrong on the day of the exams?
In wales I would be saying try and speak to a careers Wales adviser. I assume there is similar in England?