Medical schools are looking for 2 things (IMHO) -- people who can pass their curriculum and who have the right personality to be a doctor. More volunteering, strong letters, more shadowing, etc., can't help with the first requirement -- demonstrating you can pass their curriculum.
If your lower grades were early in college, then you can easily show that you've overcome these academic issues. But if the lower grades were more recently, you made need some help. You might need to take additional post-bacc courses while your application is being processed. This way, if you don't get in and you have to reapply, you'll be able to "demonstrate" that these lower grades were in the past and your more recent work is representative of your abilities. See what you're premed advisor or a trusted faculty member has to say about this.
Regarding your question about what to put in your personal statement, here's my suggestion. For any issue, you should take 2 or 3 sentences (keep it brief). State the issue (low grades), state why they happened (illness in the family and surgery for yourself), and show that you finished strong academically (which demonstrates that this issue is in the past). Be careful not to say anything that might sound like you're making excuses (eg, they would not let me reschedule my finals after my mother got sick). Please understand that I'm not suggesting you are making excuses. I'm just cautioning you to not say anything that could be misunderstood as someone making excuses. Just keep the focus on you -- "I got some low grades, family illnesses took precedence, look at my grades now".
Best of luck with this.