One of my friends says “nothing has been proven true” regarding the jabs and what they’ve done

What are some things that are actually PROVEN and not just “coincidences”?

Like I’ve had two relatives have heart problems and clotting about a year after getting the Moderna jab. But how do you prove that’s what caused it (even though I’m sure that’s what it was)?

Edit: Thanks for the comments. Here's the first response: "I’m literally the target demographic to be killed from covid vaccines according to conspiracy theorists and my heart is healthier than it’s ever been. Refusing the vaccine for a job is retarded lol. Some people have always had adverse reactions to vaccines and will still have them in the future, correlation =/= causation, it’s just a fuck ton of fear mongering. Don’t even get me started on all the retards taking ivermectin."