Patience is the key. Things won’t be the same as they once might have been between you but you need to support and help them rather than resent them for it. But equally don’t stand by and become a punch bag too; if they are treating you bad, anxiety is a reason why but not an excuse for it.
It’s a fine line between letting the odd thing slide and being taken advantage of, so be careful and make sure you have a support network to fall back on as well.