How to help/run my fathers roofing company?

my father has owned a roofing company for the last 28 years. For about 25 years he did great, but in the last 3 years he hasnt got many calls. i was thinking because of his advertisement. he is in many local yellow pages, has a website (could be improved) and a few other local advertisements. can anyone suggest ways to get things going again? i would eventually like to take over his business and need a little help