Wall'o'text - problem with my son's boyfriend

I'm the evil m-i-l, and my daughter is the evil princess.

Usually it's questions on how to deal with meddling inlaws, but I'm on the other side of it.

My oldest son (18) has aspies. He's never been good a making, or keeping, frienships. Last year, after moving schools, he made a group of friends who are really solid. That's great.

In that group of friends was a girl he had a massive crush on, and it was obvious she had a crush on him. After much prodding from *everyone* he asked her out, and they've been together since.

In the meantime his girlfriend has come out as transgender and now identifies as male (F). No dramas there; I'm really proud of my boy, that he wasn't a superficial sod, and continued to love the person rather than the gender.

F's family, on the other hand, haven't taken it well at all. There have been threats of suicide from F's mother, because "how could you do this to me, I've lost my baby girl", and F's father blames my son (L) for some reason I can't quite understand.

So I feel bad for F, and give him quite a lot of leeway. No one should have to put up with that kind of rubbish, especially not from family.

Here's the issue. My daughter (T), really doesn't like F. T doesn't care about the gender thing, but she dislikes that F is such a flirt. L informs me that they have a poly relationship, and that he's fine with it. T maintains that when F started flirting with a boarder we had for a while (pretty 19 year old female), including cuddling with her, at our house ... well T thinks it's disrespectful as hell, and pretty much cheating. I'm inclinded to agree, but L is a big boy, so it's up to him what he'll put up with.

Some background on T. She's difficult, there's no denying it. She has abandonment issues (she was 3 when their Dad and I broke up), which make her prickly as hell at the best of times. In the last 12 months she's been drugged twice, one resulting in rape (she wasn't conscious for it), and she was raped again in March. So T's a bit of a mess, she cuts, and she's overdosed twice.

The last overdose is when the problems with F became apparent. The boarder (K) and T had a suicide pact. K watched T take over 70 panadol, but decided to not go through with it herself. K also decided to NOT tell anyone about it for a few days - it wasn't until T started to look sick, that K started to panic and let the cat out of the bag. We got T to the hospital, she was given antidote (which sent her into anaphylaxis), she was given adrenaline (and went into cardiac arrest), and then she was given something for the cardiac arrest.

T is fine now, physically, and she's getting help for the mental stuff. It's a slow process, but she's trying and will get there eventually.

So. I had no clue about the suicide pact until a little later. I lost the shit, and kicked K out.

F decided that I was being too harsh on K, after all it was T's choice to attempt suicide. I wasn't thrilled with that, but let it go.

L decided to ask F exactly why he didn't like T, at which F became agitated and confronted T with a fb message - basically T's ideas about relationships are sick and archaic ('cause T thinks poly relationships are usually a tool of the patriarchy - she's 15, give her a break), T has no self respect, T is a horrible person, and T is cutting and attempted suicide just for attention - and T got herself raped because of her lack of self respect.

T actually ignored it. More than I would have done. I pointed it out to L, who felt a little responsible because he'd complain to F when he and T were fighting.

I personally think that you should be able to bitch about your sibling, to your other half, and not have to worry about what your other half is going to say to your sibling. Clearly F has no problem putting L in a really difficult situation.

It all settled down to a simmer, until T posted one of those silly facebook memes. "I'm the only one allowed to mess with my siblings, if you touch them watch out" type of thing.

F decided it might be a good idea to reply (publicly) that T is this, that, and the other, and blah blah blah. Two of my sisters got a little bit involved, but backed off when asked, but F just kept on.

T at this point point blank told her brother that his boyfriend is a $$/&/#@/^ and that if L didn't do something about it, he could forget about having any kind of relationship with her.

My sister in law calmed the situation between L and T, and arranged to mediate between T and F, because she loves my kids and that's what aunties do.

Now F has decided that M (s-i-l) was attacking him - which is utter rubbish, M has been nothing but supportive of F through his coming out journey (as has the rest of the family), to the point of taking him clothes shopping and such.

L tried to talk F around, but F will have nothing to do with it. Now F tried to explain to M that F was feeling attacked, and somehow managed to compare M to ISIS and Donald Trump.

I've explained to L why that's such a terrible metaphore (yay, aspies ...), but L says that F thinks L has nothing to apoligise for to M.

So. I'm just sitting back, and trying to keep a low profile in all of this ... but I'm so damn cross.

Advice? Thoughts?