How to tell my shop owner he's the one stopping us getting customers? Please read?

Me and my friend manage a shop together, we love it and we were doing a great job. However, the shop owner tends to come into our shop, sit near the door and do nothing but stare outside with a very bored expression. We never get customers while he is there, but when he leaves we get them again. He is a very lonely man with no friends, so I feel sorry for him, but he does nothing to help himself get friends.

He lived with his daughter, and before she left home he came into the shop for about 2 hours a day, sitting silently alone staring down everyone who walked past. Now she has left home and he says being home makes him miserable, so he will come into the shop every day and stay for 5-6 HOURS. Meaning we get no customers.

I told him once that some people get nervous being stared at and it will make them avoid the shop, and he said he doesn't think it's a problem.

It's really awkward, he does not have a book or phone, just sits and stares. We only get customers in the morning now, before he comes in (he always has a lie in) and our profits are majorly down.