In order to qualify for an Adult Dependant Relative visa you will need to satisfy UK Visas and Immigration (UKVI) that:

• You are the parent aged 18 years or over, grandparent, brother or sister aged 18 years or over or son or daughter aged 18 years or over of a person who is in the UK and that person is over 18 and either a British citizen, settled in the UK or a person with refugee leave or humanitarian protection status;

• As a result of age, illness or disability, you require long-term personal care (that is help performing everyday tasks, e.g. washing, dressing and cooking);

• You are unable, even with the practical and financial help of your family member in the UK, to obtain the required level of care in the country where you are living because it is not available and there is no person (close relative, home-help, housekeeper, nurse, carer, care or nursing home) in your country who can reasonably provide it, or because it is not affordable;

• You will be adequately maintained, accommodated and cared for in the UK by your family member, without recourse to public funds (if your family member is a British citizen or settled in the UK, they will be required to sign a 5-year undertaking to this effect).

The exact requirements you will need to satisfy will vary depending on your circumstances.  You may want to speak to an immigration lawyer for expert advice.  

The Adult Dependent Relative visa route is only available to applicants outside the UK. It is not possible to switch into this route from within the UK.

Even if the person applying for an Adult Dependent Relative visa does experience the high level of ill health required by the second criterion, the third criterion is even harder to meet. Most sponsors who are able to afford to maintain and accommodate their dependent relative for five years will find it hard to prove that they cannot afford to provide care for that relative in their country of origin.

If you are granted an Adult Dependant Relative visa then you will be permitted to enter, and remain in the UK, indefinitely.

The circumstances in which an adult dependent relative of a British citizen or person settled in the UK may qualify to settle permanently in the UK are limited. Non-EEA national family members and extended family members of EEA nationals who are exercising Treaty rights in the United Kingdom enjoy more generous provisions under the Immigration (EEA) Regulations 2016. In certain circumstances, British citizens may also be able to bring their adult dependent relatives to the UK by relying on these provisions.

The Adult Dependant Relative visa application carries a high evidential threshold in order to meet the above second and third stages of the requirement, namely that as a result of age, illness or disability, you require long-term care, which is either not available in your country of origin or there is no person in your country of origin that can reasonably provide it. In order to meet these requirements, you will need to obtain expert reports demonstrating that these requirements are met.  

The type of expert and expert report you will need will vary depending on your circumstances.  You may want to speak to an immigration lawyer for expert advice.