Start with information
On paper or in a private document, list money coming in, essential bills and their due dates. Estimates are okay to begin with. Do not enter account numbers or passwords into shared notes.
Choose one reminder
Try a calendar reminder for one bill or a regular time to check the list. If someone helps, agree what they can see and what decisions remain yours.
Get advice for bigger decisions
Benefits, debt, trusts and tax depend on local rules and your circumstances. Use a qualified local adviser for those decisions. The linked US planning resource is background reading, not a recommendation to buy a financial product.