Jacket of All Trades - A person who can do everything, but can't remember anything,

A person who can do everything, but can't remember anything, not even their own name.

'He's a jacket of all trades, but he can't remember his own name on a good day.'

'She's a jacket of all trades, but I swear she can't remember where she put her keys.'

'He's a jacket of all trades, but he forgets everything, even his own birthday.'