Any suggestions how to plan for in law funeral expenses?

My mother in law is in her seventies. She recently lost her job and with it her only source of life insurance. My husband's siblings are not too financially savey and I am certain have not considered this. I know my husband and I will be looked upon when the time comes to help with funeral expenses. I would like to take out a small life insurance policy on her now so that when the time comes if they have no resources we would have this. I don't necessarily want to "pre-plan" or share this idea with her or the family. It would solely be for me and my husband to fall back on should we need it. We are pretty secure ourselves but would not be able to come up with a large amount of money on the spur of the moment. Any sugggestions would be appreciated.