Kinda freaked and need advice.

So I'm driving my dad (age 87) to the store today & right in the middle of talking to me he goes "wait a minute..."
I look over and his head is down in his chest...
I'm kinda freaking asking what's going on etc.
Anyways, he lifts his head acting really weird and says he just had a blackout.

My mom is constantly having dizzy spells and can barely walk.

Basically, both of them are entering the ends of their lives and I'm kinda freaked.
I still think of their deaths as coming 20 years from now, but after this morning, the scary realization is hitting me that the death of one or both of them could happen at any time.
I got no clue what to do if one or both of them suddenly dies...

Any advice?