accident at work, reoccurance

Hello

A friend had an accident in July 2008 due to not receiving manual handling training. Liability was agreed and he received compensation. However, he has had a relapse and should he make another claim from this reinsurance. He had no support in his recovery, and bullied by managers e..g. remarks like we all have bad backs, you're an old man, he was sworn at, got told "have you been shot" when he was limping due to his sciatica, all the team moaned when he was in pain, they said it distracted them, they did not follow gp's instructions considering they wrote saying no lifting or bending, their final occupational health never assessed him in person.

the personal injury medical expert agreed it was due to  the injury but 18 months after would not be, but would this be a case for stress at work

if liability denied would he still get loss of earnings as he would have still worked there if he had not suffered bullying

thanks
tom