Do not cap a word after a dash unless it always has to be capped.
...He was on his way to -- to visit her in the hospital.
...She helped him to -- helped her to the couch after she fell.
When there is a complete chance of topic after the dash, paragraph the next sentence. Of course, the paragraphed sentence is capped.
...A He was on his way to --
I believe that he worked nearby and that he was on his way to work.
Happy punctuating!
Margie