The nice people at Linked In had a piece about what caregiving can do to your job and job prospects.
This piece is about elder care primarily, but the bottom end of the piece has ten points of advice that are worth considering. The very first is to tell your employer what’s happening. I’d qualify this because you really should always treat HR like the enemy but generally that’s good advice. Let them have some idea of what the floor and ceiling are so that colleagues can forecast how much to put on your plate and at what rate.