My Sister, 75 Yoa...has Had 2 Episods Of...loosing (almost Fainting)

my sister, 75 yoa...has had 2 episods of...loosing (almost fainting) and falling down. this last on she tried to walk and sat at a table....right arm shaking and snot running from nose. clear, no blood. she seemed to come out of it within about 5 minutes. could it be a stroke?