Usually the NHS arrange for vetting to happen through an agency in Manila, and sometimes the out provinces so he would have to check with the overseas employment agency (or whatever they call it now in the Philippines) to see when they are next there.
As usual though, agencies aren't free as they believe in ripping off fellow countrymen from the start.
The NHS is so desperate for nurses some hospitals will ignore the agency and employ someone directly if they are good enough.
Get a list of as many hospitals as you can, and get him to write to the 'Employment Manager' in each of them. Make sure he mentions he already has relatives here as it makes access easier.
He may need to come over here for interviews, so he would have to ensure they are all the same week. After that he may have to go back to the Philippines and apply for a work permit if he gets a job, but I would imagine the NHS has direct contact with the immigration to sort it out.
Try and find hospitals with Filipino's already there.
It may be advisable to search for a CV template and fill it in as best you can for him, and then get him to do the rest. Always provide a polite cover letter explaining what he loves about the job, and all the usual crap you'd put on a job application.
