Something like "I'm here to listen whenever you need it" is probably good.

I'm like Curupira, usually when I'm sad I seek physical comfort so I tend to try and get a lot of hugs from my family and friends. It's not really a phrase but just spending time with me is probably the most helpful. Even if they're chattering away or we're sitting and watching a movie, keeping me busy is important and I take it as comfort because they want to hang out with me.