1) I wasn't aware that Mr Frum had a medical degree.
2) Arafat seems to have taken a turn for the worse (or better, depending on your point of view) very quickly. This isn't consistent with AIDS.
3) All his health problems are fairly common in people in their late 70's.
4) Arafat's wife has shown no signs of illness.
Of course, non of this is conclusive proof, but there is no evidence whatsoever that I'm aware of that suggests AIDS.
You're assuming she actually had sex with him? Rash assumption I'd say.