I would think that means "like this". So more literally I would translate this sentence as "Thank you for always being there for me like this" or "Thank you for always taking care of me like this".
As for the main verb according to jisho there are several possible meanings: () "to keep company", "to listen to", "to look after"...
I personally often see how the particles like or get omitted so I suppose this is also the case in this sentence.