you appear to be mixing two questions in one.
Renting the property is relatively straight forwards although there is more to it than just the contract, for example, it is a legal requirement to hold any deposit in a government backed scheme. Also you must have buildings insurance that is notified that you are renting, annual Landlords Gas Certificate etc.
http://www.propertyinvestmentproject.co ... al-issues/ Your original question mentions that your mother is in a home because of her Alzheimer's Disease. As it is 'her house', are you legally in a position to rent it out? Does she have capacity as per the Mental Capacity Act? I'm not in the UK so the exact legal process may not be entirely accurate but if she hasn't got capacity, do you or one of your sisters have Enduring Power of Attorney or Receivership? If not has someone else and will they give permission?
Again, different law in the UK but I think the situation is that your mother's assets are taken in to account when paying for care, so if her savings run out she may be forced to sell the property. If you have placed a tenant in there but the rent doesn't cover the costs, then you may find yourself liable.
In short, it can be done but you need to be clear that you are acting correctly or you may be in an even worse situation.
Try the following for free advice:
Age UK:
http://www.ageuk.org.uk/publications/ho ... ications-/ They have a help line number on the web page or they have a shop in Lancaster, 14 New Street which may be able to put you in touch with an advice centre.
Citizen's Advice:
http://www.citizensadvice.org.uk/morecambecab/Alzheimer's Society:
http://alzheimers.org.uk/site/custom_sc ... Code=12642Alzheimer's Society
Altham Meadows
Bartholomew Road
Westgate
Morecambe
LA4 4RR
Tel: 01524 402610
Good luck.