Friendships/Connections changing

An older friend is having health issues. How do you deal with and accept that life is changing and you have no power to change what is happening? I have the power to choose how I feel and want to feel sad because I feel I am losing someone that has been a trusted friend and someone I truly have a connection with and is the one close friend that lives close to me, other close friends live out of state which makes it harder to meet for casual dinners, etc. I am already feeling disconnected due to what is going on in the world and every time I get the energy to put toward meeting new people I have setbacks. My friendships right now are with people I have known for 20 or 30 years. I want to make new friends that live near me and add to my already great core group of friends but feel not only am I having difficulty meeting new people that are worth putting in the time and energy for but I am losing friends due to moves/distance and others getting older and being less available.