'à qui' or 'qui'

Question

'Mon frère qui habite en France.' I would assume it's wrong to use 'à qui' or 'auquel' in this context, but I don't know why? When is it most suitable to use 'qui'?

Accepted Answer

Bonjour Katie,
You are absolutely right. You cannot use "auquel" or "à qui" here as they mean "to whom / what, which" whilst "qui" means "who". 
Have a look at the examples below:

Mon frère à qui habite en France = My brother to whom lives in France
Mon frère qui habite en France = My brother who lives in France

Mon frère qui je pense = My brother who I think
Mon frère à qui / auquel je pense = My brother whom I am thinking about

I hope this is helpful.
Bonne journée !