I wouldnt jump to too many conclusions here without a lot of investigating and a lot of backing up with evidence!
Did you see that the h/h 2 doors away is headed by Alfred HAzell, then has his wife Harriet Hazell and a baby, then brother-in-law Daniel HAzell? Then mother Eliz. and nephew Thomas as you mention.
Bro -in-law could be step brother, could be his fathers from a different marriage. If it is bro-in-law as we know it, wifes sister, that implies that a HAzell married a Hazell in that family. Maybe your Elizabeth did the same.