Need In-Law advice

I'd do it. One day you guys will have kids, bam, babysitter is ready to go. Also at some point in the future and they will start needing your help with stuff (my mother in law does) so it would be a much closer drive, only one lawn to cut that kind of thing. Also at his age he has a wealth of knowledge that you can use around the house. On a side note I'd never buy a house again. Costs too much to maintain etc.