if your friends are gonna leave you just because you come out, they aren't true friends
if you wish to keep your last friend, just ask them if they support LGBTQ!
if they dont, just dont come out
if they do...
then come out to them!
if they ask why you're asking them that, just tell them you're just curious.
if that doesn't work, just tell them you wanna know because you wanna tell them something but you can't do it until they answer.
if they ask what the something is, just tell them it's not exactly LGBTQ related.
if they then question why you asked them if they support it but the thing isn't related, just tell them to calm down and answer.
if they don't answer...
then just figure out another way to persuade them into answering so you can come out, my fingers are tired and i cant think up of anything more