My DH and I have been together for around 10 years. First 5-6 years I got along with his mum well, then after we had our child we've started having issues.
Just after my child was born MIL insisted she needs to come visit within the first few days of his life and, after a complicated birth, I wasn't so keen. MIL kept calling my DH and insisting, eventually called him and burst into tears saying that she actually suspects she's got cancer which is why she wants to visit because she might not have long left. Obviously her son (my DH) and I were both worried, given she had cancer about a decade before this and she used to work in the medical field so surely she's got some clue what she is talking about. He encouraged her to go to the doctors which she did eventually. No cancer.
A couple of years later she once again suspected cancer because she's got random pains that can't be explained. Suspected she's got cancer. Coincidentally at a time when we had renovations going on in our house and I went to stay with my mum overnight quite often (so that our child doesn't live in the middle of a building site when certain work is going on / wet paint / too many dangerous bits sticking out of walls or floor). Everyone panicked and organised many visits. No cancer.
Now, she's also announced that she thinks a mole is cancerous. Coincidentally at a time when my child gets super excited to see my mum but is a bit meh about MIL's visits. DH is panicking but I just can't help but think of the boy who cried wolf...