I would consider her to be a cross between 4a and 3c.
My hair is 4a but there are parts that are 3c. Her individual strands look like a mix between the two, IMHO.
Again, the hair typing system is flawed.
I agree with ladies who say that people will label their hair in the 4s when its really in the 3s. I think that goes to their perception of their hair being unmanageable, too "kinky" and any shrinkage. I think it also goes back to what they consider (even subconsciously) to be manageable hair, which is usually in the 2s or 3a or 3b. Since they see their hair as unmanageable, they automatically assume its in the 4s (4 hair can be very manageable btw) when it may be 3b, 3c or maybe a 3a. My mom is like that.