Dad thinks mom is alive. She recently passed. He has a big pic of her and placed it in her chair. He covers it with blankets. He talks to the pic and will sit there rocking her. He said she doesn’t talk and he can’t get her to eat. What should we do?
Eventually, he may forget Mom. As long as he is content, let him be.
It's a bit late now, but the life-sized picture idea seems to have gone a bit awry - presumably somebody well-meaning gave this to him, he didn't have it printed himself.
I don't think there's any point in trying to remove it as long as he isn't becoming distressed by getting no response. Meanwhile, what about putting together a varied collage of pictures of your mother so that you can talk to him about her and their life together?
I'm very sorry your loss. I hope this reaction of your father's isn't adding too much to everyone else's grief. It must be very hard for you all.