TT #697 · Parashas Ki Seitzei · Seventh Aliyah · Passuk 25:06
And it shall be that the firstborn that she bears shall succeed to the name of his dead brother, so that his name shall not be blotted out from Israel.
Torah Temimah points to Sifrei / Yevamot.
TT lemma: הַמֵּת.
הַמֵּת – רִבָּה: מֵת רִאשׁוֹן יִבֵּם שֵׁנִי, מֵת שֵׁנִי יִבֵּם שְׁלִישִׁי.
English: “The dead” — this is an inclusive expression: if the first dies, the second performs yibbum; if the second dies, the third performs yibbum.
On the daf / in context: The singular “the dead” is read expansively to cover successive deaths among the brothers.
Ribbui from the definite article / singular form.
Yibbum (or chalitzah) continues down the line of brothers as successive deaths occur.