I have a feeling my mother is about to have a seizure.?

If your Dad really did want to come home because he is watching a movie on his birthday, that's pathetic. If you feel she is, call the ambulance at the time. You need to get her the medical care she needs. When she is, or if she is, hold her head, because you don't want her to bite her own tongue. That's the only advice I can think of at the moment, sorry. Call the hospital and ask them what they think too.