I need some legal immigration understanding if anyone here who can share some thoughts.

Here is the case:

I have a friend who currently holding a 6 year Work Permit Visa that will due on 2013. Unfortunately, last mid of the year 2008 he was redundant by the company whom where he took his Visa. This Company imformed the Home Office that my friend is no longer working with them and now working with different company with different Job related descriptions. Since his Work Permit Visa is still due on 2013, my question is, is he still legal to stay in the UK regardless of his unrelated job description and working with different company?

He is worried that Home Office might soon informed him with bad news. As he too want to have a vacation in the Philippines to be with his family without worrying of getting back to UK.

Thanks in advance for any positive legal responce.