Janet,
I have to say, were I in your shoes I would cook for myself and Tony and if Billy wants to eat it fine - otherwise it's leftovers for Tony the next day. You have told us that Billy doesn't pull his weight around the house - he is a grown man and I wouldn't be catering to his dietary needs and wants every day. Maybe a nice dinner on Sundays that you can eat together - but not every day. That would be me but you are nicer than I 
A crock pot is fabulous investment and I believe you find a nice large one for about $20-25 - I guarantee it will pay for itself in a month because you can make cheaper cuts of meat tender and most of the time, the prep is minimal and you just leave it for the day! I use mine a lot more in the winter and love making soups. Tony would probably love stews. Only caution I would have is for chicken. I have found in the years I've been using mine that white meat doesn't take the amount of time it says and dark meat chicken is much more suitable for the crock pot.
Do an internet search for a year of crock pot cooking (or something like that). A lady with two children used her crock pot every day for a year. She has pictures of the ingredients and the final product with comments on what she liked/didn't like and what her kids and husband thought of the meal. You can access the recipes alphabetically or some other subgroups. I've tried tons of hers!
Sharon
