Losing friends to death becomes more frequent later in life, and for solo agers, each loss can shrink an already-limited support network in a very concrete way.
Grieve the loss, and acknowledge the practical gap
It's reasonable to feel both grief for the person and anxiety about what their absence means for your own support plan — both are valid and can be addressed separately.
Rebuild deliberately, not just passively
Treat a friend's death as a prompt to actively add at least one new connection, rather than assuming your circle will refill itself.
Consider friend groups with some age diversity going forward — a circle entirely of same-age peers is more vulnerable to this exact compounding loss.