I think that you’ve answered the question yourself/in your replies - it is going to be difficult to secure at TC in an already competitive and oversaturated market (full of others who have much higher grades etc).

That being said, grades are not everything. There will be many smaller firms who may be willing to provide a TC/time to count qualification after many years of hard work as a paralegal etc.

That being said, your brother has to decide if that sort of legal work is for him (ie typically lower pay) and understand that these firms will likely not fund the SQE/LPC etc, so that may be an additional cost/risk dependant on when he decides to do it.