Your mom has probably been one of your greatest cheerleaders as you grew up, but now she's in need of some cheering up herself. You don't have to spend lots of money or be a trained psychologist to help her through a down time. Instead, call her more often, let her know she's important to you and spend some time with her. Have your kids draw her some colorful pictures or bring her some flowers. Be available for her to talk to if she's working through an issue or grieving the loss of a loved one.
Spend time with her. Perhaps she's just feeling lonely or unneeded, particularly if all her children are grown and busy with their own lives. Make time in your schedule to visit with her, take her to lunch or spend the afternoon looking at old pictures with her. And don't just visit on special days, such as her birthday or holidays, since she might believe you're just doing that because it's expected. If she's feeling down, go visit her "just because" and spend a few hours just relaxing together.
Send her occasional "thinking of you" cards, even if you just live on the next block. Receiving personal mail often brightens the day for someone who's in need of a lift, especially if it reminds her she's loved and thought of fondly. Or drop by with a small gift that is meaningful to her: a new book by a favorite author, a flowering plant for her garden or some new pictures of her grandchildren. And don't underestimate the value of picking up the phone to chat for a few minutes every few days. Always end the calls by telling her you love her.
Do something with her that you know she enjoys. Take her to a favorite tea shop for a special "ladies' lunch." If she loves gardening, spend a sunny afternoon working out in her garden with her. If your mom loves to bake, a day spent with her daughters and grandchildren, teaching them a few of her signature cookie recipes, will likely be a big boost to her spirits. Ask for her input on a decorating or child-rearing issue, so she gets the positive affirmation that her opinion still has value to those she loves.
Go to church or Bible study with her, if she finds comfort in her faith. Send her little notes with favorite Bible verses on them, or get her a recording of some favorite hymns. Let her know others are praying for her and wishing her well. Take her along to help with a local ministry or community service project. The act of helping someone less fortunate than you are is often a huge boost to your own spirits and sometimes also helps you put your own problems in perspective.