\def\fauxfontheavier{%
    \sbox0{x\xdef\testF{\the\font}}%
    \sbox0{\fontseries{sb}\selectfont x\xdef\testFsb{\the\font}}%
    \sbox0{\fontseries{mb}\selectfont x\xdef\testFmb{\the\font}}%
    \sbox0{\fontseries{tx}\selectfont x\xdef\testFtx{\the\font}}%
    \sbox0{\fontseries{m}\selectfont x\xdef\testFm{\the\font}}%
    \ifx\testF\testFsb\fontseries{b}\selectfont\fi
    \ifx\testF\testFmb\fontseries{sb}\selectfont\fi
    \ifx\testF\testFtx\fontseries{mb}\selectfont\fi
    \ifx\testF\testFm\fontseries{tx}\selectfont\fi
}