Is it normal for the elderly to withdraw if they were once very social?

My mother turned 88 in May. My husband and I spent all winter with her in her Colorado home. It was decided that she cannot be alone and before we got there she was not taking care of the house, eating very well, etc. I have moved her back to Minnesota in a senior community living facility. My mother was a social butterfly all her life until this past year. She kept cancelling on her friends to play bridge, go out to dinner etc and she continued that all winter while we were there. I thought it might be because of her unwillingness to drive and her friends were picking her up all the time and calling her to remind her of brdige, etc. Now that she is in a senior community she still will not socialize much other then at the meals. She won't play bingo, go to exercise class, but she will play bridge when they need her. I have asked her many times (her brother also) to go to lunch with me at the mall to get out and she says no. The only places she will go is to the doctor's office and the casino and I am the one that takes her to these places. Is this normal to withdraw from everything? Her friends in Colorado were fearful of her memory and were watching after her and checking on her a lot. She has had three major death losses in the last year also. All winter she kept saying, "Why am I alive?" or "I made it through another night." After not being around my mother consistently for 35 years, I am finding it very difficult to understand her ways now and her personaltiy changes. She was not much of a family person, grandmother to my kids, etc. and now I am taking care of her and she is completely trusting in my decisions even though she also made the decision to move to Minnesota but she wants to go back to Colorado. Her house is sold now and there is no one there to look after her; no family.