The OP is right. His/Her friend is wrong. The correct answer to the OP's question is "no".
The explanation is as follows: there are two options available for the US expat to reduce or avoid US tax. One is the Foreign Earned Income Exclusion. The other is the Foreign Tax Credit. Whilst you could technically use both, you can't use both for the same income.
Whilst the FEI is limited to $91,500, the FTC is unlimited. So as long ad you are paying more in the UK, the FTC will knock out US tax, since UK tax is higher than US tax.
The FEI is only really helpful in countries with no tax or lower rates than the US. The only reason why a UK resident would want to use the FEI is for example a non-Dom claiming the remittance basis with non UK and non US earned income, or someone over 75 (with a corresponding enhanced UK personal allowance), no dependants, and filing as single, and with a little employment income (say £10,000) where the UK tax doesn't cover the US tax. It won't help for non earned income such as pension or investment income, so some pensioners may end up paying US tax on their pensions.
The above answer assumes there are no other income sources, even those which are in a tax free wrapper in the UK (such as ISAs and SIPPs)
With regards
Andrew