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.