You should check out the police's accident report for the accident. This
report includes culpability of all parts involved in this accident. You can
sue for indemnity according to these culpability numbers. For instance if
your client has 2/8 culpability while the other party has the other 6/8
then you can ask for the 6/8 of your damage from the other party or his
insurance company. Do not wait too long as there is a time limit for this
lawsuit.