my mam is car wo not start and we think it is due to the starting motor

first thing to check is for dirty or loose battery cables way to clean is remove cablle scrape inside edge & or brush it with wire brush & replace & if that dont do it then jump start it with another car or battery then drive it to any shop ask to check the charging system cables battery alternator starter.. first then that goes wrong is the cables or loose belt.. starter on all cars about same place right side of motor down by transmission just follow the red wire from battery

You will find the starter motor down the back of the engine towards the bulkhead.

under inlet manifold,uaual fault is small wire to s/motor corroded,remove and clean refit and could cure,fiddle to get to.