Rant: this is the kind of crazy I woke up to this morning!

So here's info you'll need to know:

I live in a house with -

My SO

My 16 yo son (Seth) from previous relationship

My 12 yo son (Gavin) from previous relationship

Have legal custody of my 10 yo niece (Kaylee)

Mine and my SO's 15 month old son (Landon)

My SO's father (Ashley) - yes you read that right, father -

Ashley and I got along great at first, then he started complaining about every noise, footsteps, TV, me yelling at the kids, etc. He's 73 years old, he doesn't really have a "sleep schedule" but he usually wakes up anywhere between noon and 3 pm and stays up until around 5 am. He has his own "in-law apartment" in our basement complete with his own bathroom and kitchen.

Recently, he and I got into a big fight because he was upstairs in my living area playing with Landon when Gavin came to talk to me because he was frustrated with his homework. Ashley got upset with Gavin because he can't tolerate anyone expressing emotions other than happiness or he says it's "elder abuse". He ended up causing Gavin to run to his room crying. This happened about two weeks ago.

I woke up to Seth texting me this:

UPDATE: I found out another thing - my niece had all of a sudden told me she wanted to go to therapy/counseling but she wanted to do it alone, I didn't think much of it until I talked to my older son again about the situation and told him Kaylee would be going to therapy. He immediately was concerned and told me that during the conversation he'd overheard, Ashley told Kaylee to say she wants to go to therapy alone and then tell the therapist that I abuse them! At this point my SO confronted his dad, who admitted to recording me, but said, "he doesn't remember saying any of that stuff to Kaylee". We don't believe him and my SO told him he needs to find a new place to live!