Universal Credit is normally claimed by the person who is responsible for the household, so you cannot simply claim in another adult’s name. If your family member cannot manage their claim or financial affairs, you may be able to become their DWP appointee, subject to the department’s approval. If they live with a partner, they will usually make a joint claim, while dependent children are included in the household’s assessment rather than making separate claims. Check the official GOV.UK guidance or contact Citizens Advice for help with the relevant process.