Albert and his work (theoretical, not real) dealt with theory of relativity? (5,2,7,4,5)

I believe the answer is:

blood is thicker than water

'theory of relativity?' is the definition.
(proverb about loyalty to relatives)

'albert and his work theoretical not real dealt with' is the wordplay.
'not' is a deletion indicator.
'dealt with' is an anagram indicator.
'albert'+'and'+'his'+'work'+'theoretical'='albertandhisworktheoretical'
'albertandhisworktheoretical' with 'real' taken out is 'btandhisworktheoretical'.
'btandhisworktheoretical' is an anagram of 'BLOOD IS THICKER THAN WATER'.

I've seen this clue in The Guardian.

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