Aww, sounds like you are having a really tough time... Sorry, I did laugh though about your mom asking your friend if you had told her your "secrets"... wow.... LOL But I do feel bad for you.
I just wanted to chime in and say, try not to frett too much about your 3 year old's speech delay... this happens with a lot of kids and from what I see it's usually at least partially due to the older siblings speaking for the younger ones... the younger one makes some noises and guestures and the siblings go "Oh, he wants this." ect. ect. I have seen it happen, since I have 5 younger siblings! Your little boy will grow out of it though, I promise!!
Keep your chin up and hang in there. I know it's really hard, but I agree, it would be best if your mom found somewhere else to stay.... I can only imagine how tough this must be for you.