Am I entitled to my late father's family jewelry and vehicles if he remarried?

If he was married for only a year, most of his assets would be his separate property unless he agreed to merge all their property together [likely never occurred to them]. Any community property she already owns half and the other half would be split between you [if you are in California]. If he made a Will, his half goes to whomever he named in the Will. If it is all separate property, than the two of you split 50-50%. It sound like it will be messy figuring out what property is what. ?Try to be nice with her and see if something can be worked out [if she has no children, put the items in an irrevocable trust so you get it all on her death and she can not sell it while she is alive but gets to use it.

Without a will or trust, Dad's separate property would go half to wife and half to child, or if more than one child one third to wife and two thirds to children. Probate Code 6401. Dad should have a will, or a trust if he has real estate.