My mother earned interest on her money in savings bank account.

Now she is worried if she can use that money or is it wrong to use that interest money? Could you please help?

Also can she invest again in savings account to earn more interest?

It is from a bank in Pakistan, so Muslim government and the bank is owned by the Govt of Pakistan too.

She must give in charity 50% of the interest on poor believers, and she can own the rest and dispose of it as she likes