I happen to know of a case extremely similar to what you describe.
It was extremely painful for the survivor, excluded, even from the deathbed of (his/her) partner.
I would not wish that scenario on anyone, even if I would not take part in that sort of a relationship myself.
As for the specific of "marriage", I would say that is a "religiously defined" union between male and female.
That is why, besides a Justice of the Peace, only ordained ministers of a recognized religion are allowed to perform a marriage ceremony.
( I think I've got that part right. )
So, let's go the secular route, and create the "Spousal Contract", purely a legal construct, that guarantees certain legal rights, to legally recognized unions between consenting adults.
I am sure not only gays and lesbians will get behind such an initiative, but also polygamists, polyandrists, communalists, and other proponents of various types of familial traditions.
All of the usual benefits of marriage, inheritance, insurance, etc. would apply, modified to apply equally & fairly to groups greater than two (2). [ i.e., survivor's benefits, pensions, etc. normally recieved by one surviving spouse would not be multiplied for a grouping of five "surviving spouses", but appropriatley divided among the five survivors. ]
The only major restriction I would place on the spousal contract would be:
The Death Penalty for any couple or familial group that included or attempted to include a minor. ( under age of consent )
Suddenly, one of them takes ill with leukemia.
Suddenly, the judgmental parents of the ill person show up, and prohibit any contact from their child's life partner, and take out a restraining order.
What legal recourse does that person have?
In most statest, a "living will" and some releases on file with your personal physician(s) will completely handle this situation. If the two people in question are indeed that committed to each other, they would probably take the time and effort to make the appropriate arrangements beforehand. If there is serious mistrust between the individual who becomes ill and the "judgmental parents," it's often possible to keep the parents out of the medical decision making process and delegate those decisions entirelly to your "life partner" or your physician or other person(s) of your choosing.
In short, your example is an extremely weak case for marriage between gay persons of the same sex. The laws and procedures on the books already in most states will handle this tragic situation.
Suddenly, one of them takes ill with leukemia.
Suddenly, the judgmental parents of the ill person show up, and prohibit any contact from their child's life partner, and take out a restraining order.
What legal recourse does that person have?
None whatsoever.
Is that right? Is that fair?
Yep. Fact is, a person's lover is not entitled to anything unless that person specifically includes that lover.
For example, unless Joe provides a will that comes right out and says my lover John or Jill gets this, John or Jill, by law, gets nothing. And that is the way it should be.
And by the way, spare us this "life partner" crap. It is boyfriend, girlfriend or lover. When you marry, it is husband or wife. End of discussion.
If so, your issue is with the judge and the legal use of restraining orders. I'm personally hard pressed to see how someone could get such a restraining order issued as you suggest. Therefore, your example to me is pure and simple bull$hit.
Oh Please!!!