Yes they can, I was very fortunate with Mum's, I took it on to the ward when she was in hospital and the Ward Sister Witnessed it without charge. I also got the Solicitor to Certify a copy when I was selling her house and that was done for free as well.
Mams not in hospital so I am going to ask her GP to sign it as it was her who told us we need to get it place asap. I will ring them Tuesday to find out the cost . Thanks