Renting out a house for Mother-in-law.?

bmurph asked:

My mother-in-law inherited her fathers home free and clear, no mortgage. She has been trying to sell it for a year now. I had suggested to her that she should rent it out, until the economy turns around, and then put it back on the market. My father-in-law is terminally ill, and my mother-in-law has no time to spend dealing with the house. My wife and i have discussed renting the house for her and we would take care of the maintenance and collect the rent, and work out a percentage of the rent for doing this. We have mentioned it to her, but have not talked seriously about it yet. What would be a fair percentage for managing this for her? Is this a good idea?