How would you suggest going about dealing with an ignorant extended family member

[Athene]

Tell him if homosexuality disturbs him, then he shouldn't fuck dudes; those words, precisely.

[Brakeman]

Ask him to channel jesus in a seance because your forum has questions..

[Edwardo Piet]

Tell him that you could have sworn you heard him say a load of homophobic bullshit, but it's hard to hear him when his mouth is full of rooster.

[Bob Kelso]

"So you don't like fags, eh? Yeah I don't smoke either."

[robvalue]

I would interrupt any reference to his bigotry with a hand and say "Stop. It's not okay to speak that way in front of me". Repeat as necessary.

This would be my advice too.

"Please keep your prejudices to yourself."

If there is any possibility of a sensible discussion, I'd ask him what the "gay agenda" is. Is it wanting to be treated with the same respect and receive the same rights as everyone else? Shocking.

[Whateverist]

Okay, I will try and make this as short as possible. 

Anyways, I was just sitting with my brother in law on Christmas Eve and he was on his smartphone looking at Facebook. And then he was saying how he's annoyed by gay people and he called them fags. Apparently he has a gay friend on Facebook. And he's all like "Sorry, but I don't want fags around my kids. It's bad enough they are forcing their disgusting agenda on us".

This entire statement literally almost made me fell off my chair. For one I have a few gay friends and also I just don't think it's right to say things like that.

Anyways, he and my sister are coming over for New Years Even tonight, how do I combat this if the situation ever arises?

Keep in mind he's an avid Donald Trump supporter...so logic isn't really a possibility with him.

I feel you.  Sounds like something my sister might say, though at least she doesn't suffer from homophobia.  But she is Trump supporter and thinks some (lots of) people deserve next to nothing.

[robvalue]

It seems to me some people think like this:

"If I don't keep being openly aggressive about how much I hate gays, people might think I am gay!"

Of course, such people probably either have some fundamental reason why they think being gay is "wrong" in some way, or they are gay/bi themselves and are trying to convince themselves they are not.

People who feel secure don't need to constantly oppress others. If someone thinks I'm gay, I don't care! They can think what they like. Not that thinking I'm gay would be what I'd consider to be a negative assessment anyway. It would just be how I come across to that person.

[Aoi Magi]

He is in your house, so you have the right to kick him out.

But I am kinda curious to know what he thinks the homo-agenda is?

[Whateverist]

Pretty sure it is to get people to believe that gay people really have gay feelings and drives and don't just hate God.

[Wyrd of Gawd]

Okay, I will try and make this as short as possible. 

Anyways, I was just sitting with my brother in law on Christmas Eve and he was on his smartphone looking at Facebook. And then he was saying how he's annoyed by gay people and he called them fags. Apparently he has a gay friend on Facebook. And he's all like "Sorry, but I don't want fags around my kids. It's bad enough they are forcing their disgusting agenda on us".

This entire statement literally almost made me fell off my chair. For one I have a few gay friends and also I just don't think it's right to say things like that.

Anyways, he and my sister are coming over for New Years Even tonight, how do I combat this if the situation ever arises?

Keep in mind he's an avid Donald Trump supporter...so logic isn't really a possibility with him.

The best solution is a felony.

Just remind him that there are no marriages in heaven.  Matthew 22:30  https://www.biblegateway.com/verse/en/Matthew%2022:30  

He might start feeling gay after a billion years.