I can’t think of the exact quote right now, but I’m reminded of one to the effect of us tending to see the darkest motives in those closest to us, while being more likely to give more distant strangers a greater benefit of the doubt.
I’ve often found it to be true, where there is a temptation to judge a given behavior in a harsher light in someone we know well, than the same behavior would be judged in someone else.
I suspect your moms actual clients actually do get the benefit of a greater degree of professionalism than you do.