Praise be to Allah.Praise be to Allaah.
If he vomited deliberately, his fast is invalidated, but if he couldn’t help it, then his fast is not invalidated. Similarly it is not invalidated by his swallowing some so long as that was not deliberate.
And Allaah is the Source of strength. May Allaah send blessings and peace upon our Prophet Muhammad and his family and companions.