Praise be to Allah.
“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 Allah is the Source of strength. May Allah send blessings and peace upon our Prophet Muhammad and his family and Companions.” (Standing Committee for Academic Research And Issuing Fatwas, 10/254)
For more, please see these answers: 78479 , 105467 , 78438 , and 38023 .
And Allah knows best.