Hi Dexter - what part of the country are you in? People will be able to recommend if they know of tradespeople in your general area.
Also, when you say he is eligible, assume that he will receive a grant for the works to be carried out? You need to liase with the contact in city/county council in relation to this - they may have recommendations in relation to people to use. They'll have a process etc to be followed re signoff and payment for the works.