You not calling, as a friend, can actually compound the grief and loss they are feeling. Just pick up the phone, even if you get it wrong, just have a conversation and do your best. Your friend with cancer is still the same person they were before.
Many autistic people have trouble making and keeping friends. This has led to the myth that they don’t want friends3. In reality, they long for friendships just like anyone else. But they face unique challenges in forming and maintaining them.