Are you on acid or blind kram ? , look at the picks man , the whole entire root system looks like it can’t breath through the at least 1ft of claggy shite spread around it.
the trunk looks like it’s been hit with an excavator too along with bundles of torn out roots everywhere, it maybe difficult to tell exactly what has gone on with photos but it will be the cause of the trees problems.. my advice to the OP would get a consultant off the arb association web site local to you to do a report on it if you want it to stand up in court.