How do I help Grandpa with the loss of Grandma?

Yes, a month of mourning is nothing. Some people I know (widows) are till mourning a couple of years later. They're not holed up alone, but they're still mourning the loss of their former lives. And men tend to be more solitary anyway (compared to women). If your grandfather is still calling bingo, it sounds to me like he's doing just fine. Just be patient with him and let him mourn in his own way.

He lost her in January? As in last month? He needs at least a year to mourn.

I think your grandpa is grieving and it is better to let him go through it at his own pace. He is not ready for more activities. It takes a few months for people to come out if the shock after a loss, and then they are into full force grief. Western movies and calling Bingo is fine. I am not sure why you are afraid he will give up. It might be an idea for you to find out how grief affects a person, and how you can best help him. Some people withdraw for a while. When he says he is lonely he may be saying that he misses your grandma, which is absolutely normal and no one will fill that gap. It is great that you want to help him. Have you asked him how you can? If he says he is doing fine, or doesn't need any help, I think you need to respect that. ((((((hugs))))) I am sure you miss your grandma too.

ba8alou took the words right out of my fingers. He's not even past the second month yet! Please give him time to accept this major change in his life in his own way, on his own schedule. It is wonderful that you'd like to help him. The first step is to be patient with him.

Thanks guys. I am well aware you can be lonely in a room full of people. We go for drives and out to lunch on doctor days. He doesn't want to go out much and hasn't for years. I am just afraid of him being too reclusive. Time is a different thing entirely. I know that no one grieves on schedule. Thanks for the support

Dance, You're doing great things for your Grandpa taking him out for appointments and having lunch. I'm sure he appreciates it very much. You're a loving grandchild.

As others have said, this grief thing takes time, sometimes years. He sounds okay doing bingo and such. Just keep doing what you're doing. Grandpa's lucky to have you!

Take him for a ride, drive by houses he lived in and chat about the good old days. It's Valentines Day, bring him a red rose and some chocolates.

Listen to him tell stories about your grandmother. Listen some more, and then listen some more. He will find his own way out. Just be patient. My condolences for your loss.

It depends on what his personal spiritual beliefs are. Family isn't always the best way to get at that. They are a constant reminder of who isn't there. What would she want him to be doing? Surely not moping around missing her. Did she have a charity or hobby he could be active with?
Sometimes just writing down what he wishes he could say can be cathartic. No need to ever show it to anyone. Put it away or burn it after getting it out. Just writing it down is a lot. No need to explain anything to anyone. I even wrote letters to my younger self at difficult times and it made a difference.