Your dedication through your own suffering shows just how strong you are.

The nature of your post however warns that you are nearing your limit.
Remember that no matter how strong you are, you too can break.

I am not suggesting that you stop being there for your cousin. Only that if you intend to continue to be there for him fully then you must find respite for yourself as well.
For if you break while attempting to help, how will either of you benefit from your efforts.

I do not know what it must feel like in your position, but I know all too well the feeling of my strength wavering. Seeing that which I sought to protect endure even more because I failed to allow myself to rest.

Find your respite, so that you may be free of such things.
Endure this, and you will have found your true strength.
Not in the allure of a blade, but from within.