Prince Philip, husband of the Queen of the United Kingdom Elizabeth II, dies at the age of 99, two months before his 100th birthday.
A non-restrictive appositive is set off by bracketing commas, which come in pairs for an appositive appearing mid-sentence. If you are asking if we can omit just the one before 'dies', then no.
We include either a comma pair, if we are incorporating a non-restrictive appositive, or none, if we are incorporating a restrictive appositive.
For this case, since Queen Elizabeth II was married only once, to Prince Phillip, a non-restrictive appositive should be used.
Edit to Address Further Comments from OD
The key point is whether Prince Phillip is already clearly identified. If he is, we should use the bracketing comma pair.
I use fictitious characters to explain.
A woman was married several times. One of her husbands, H, was married just once. When we elaborate events related to H, only H's clear identification matters in determining whether to use a restrictive appositive.