Is a person who holds an orphan widow's money in trust sinful, knowing that the widow did not ask for it to be invested, and he has no means to invest it, and he fears that charity will consume it?

You bear no sin for not investing this money, because your duty is to preserve it and return it to its rightful owners, as Allah Almighty says: (Indeed, Allah commands you to render trusts to whom they are due), and the Prophet, peace and blessings be upon him, said: (Render the trust to the one who entrusted you). You should advise your sister about the obligation of Zakat on this money, and that it may be consumed unless invested, because the money of an orphan and others is subject to Zakat if it reaches the nisab and a full year has passed over it. Umar, may Allah be pleased with him, said: (Invest the orphans' money so that Zakat does not consume it).