I'm sorry for the loss of your mom, that's so heartbreaking.
One of neighbors who is 83 with diabetes is very cautious about going out. We get him groceries, but as the the pandemic wore on, we could see he was losing weight and seeming to loose interest in talking to us outside. We convinced him to come over for a meal one evening. That seemed to perk him up. He has since come over more often.
There is only so much walking around the neighborhood a person can do, but talking to people while sharing a meal helps more. It is risky, but the isolation was killing him.