Question

why did the auther said that he had a protective elder sister

Answer 1

Miss Mebbin was a very selfish, mean, and unethical lady. She was a real Mammon worshiper. It appears as if money was the sole purpose of her existence. She always adopted a protective elder-sister attitude towards money. In her presence, she would not allow any money be wasted in tips to waiters. She showed mean professional ethics, when she blackmailed Mrs Packletide. No doubt she succeeded in extorting 680 pounds, but she must have earned a bad reputation among her clients.

Answer 2

FICTION : MRS. PACKLETIDE 'S TIGER

AUTHOR said that Miss Mebbin had a protective elder sister attitude with reference to her earnest desire to earn money. She was much conscious about money that she even can' t spend a single bit of foreign currency.
Her this attitude was compared to elder protective sister attitude towards money.