My father won't let me help!?

My dad's house is in complete disrepair. He has about two acres of land that are completely overgrown, a three story house with siding/gutters falling off, black mold in the basement, and shingles that should have been replaced 7-10 years ago. The real problem is he works from home 24/7, and he won't even let me in the house to clean up the place. How am I supposed to convince him to let me fix the place up so his only real et is still valuable. I believe that his pride is getting in the way of him letting me even see the house in the condition that it is in. The fact is that he is my father and I will love him unconditionally, no matter how bad his lifestyle has gotten. Please answer if you are, or have been in a similar situation.