This is not what Twitter uses for its website or apps on Apple devices, so this user must be substituting his own font preferences. The typeface is likely a freebie as it’s based on Futura with some sloppy details and the unusual ‘f’. If you want this form of ‘f’ I think it works much better when it has a descender (this one feels like it's floating) and when other characters have this script/italic detail so that the ‘f’ doesn’t stick out as an outlier. Try Coquette.
Or something with a descending ‘f’ but no curve at the bottom, like Battling: