Usman pls look at the pic i uploaded.
its a comparison of your old civic tyre and new city tyre including the profile of your tyre and rim size.
according to this tyre size calculator your city's tyres are 3.3% larger than your civic's tyres hence your car will be travelling faster than what your speedo will be showing u.
it is recommended that difference in tyre sizes should not be greater that 1%.
the correct size for your dad's civic is
185/55/R15
ONLY IF you insist on putting your 15" city wheels on the civic.