My hubby went strange when things just were too much to handle. He didn't do very strange things, but he jumped up and down, screamed, got very upset... threw down a chair really hard to the floor... was shaking his head.... saying; no no no.... Then he began to cry really hard, with his head pressed against his pillow. I'd never seen him like that before... so I got a bit scared... felt really helpless... because he went all silent... so what could I do???
It's so hard to see the one you love hurting this much, or in your case doing odd things....
Try to stay as calm as you can... let your action show his sister, how much you care about her brother. She's going to see it! Then you can both help him.
One more thing... You need to look after yourself too... This might sound cold and I really don't mean it that way! But maybe you should do some thinking about how the future would be, you two together..... Are you strong enough to deal with this.... do you love him so much that you can live with his issues? As I wrote... I'm not saying this to hurt you! Just want you to see YOU too in this.
If you ever need to vent... PM me!
(((((((((((( Junerain )))))))))))))))