ok.. I will keep this as short as possible. My MIL passed away in July, DH has no brothers or sisters and his dad passed away 10 years ago. To say he was a momma's boy would be an understatement! This has been very hard for him, but I am finally seeing him turn it around and is able to be happy again. Anyway... his mom's 60th birthday would have been on April 1st. So... he suggested we have a birthday party for her, even though she's not here to celebrate with us. I thought it was a good idea because 1, it may help him to keep his mind positive around that time and 2... he has a HUGE extended family and with 3 very close deaths in the past 7 months it seem as if we are only seeing them at the hospital and funeral homes lately so I thought it would be a great time for everyone to get together on a slightly more positive note.
Now.. on to where I need help. I bought some cute paper and I am just going to make some very simple invitations and send them out this week, but I need help on what to say! So far I have the details, when and where etc.. and at the top I have "Even though she's not here to celebrate with us in person, please join us to acknowledge and remember Sally for her 60th Birthday!" Do you think that sounds appropriate?! Should I put something more or less? I'm just not sure and obviously I don't think this is a common reason for a party.
My second issue... is it appropriate to ask people to bring a dish. DH and I don't agree on this. He says it is, I say it's not. I feel that we are inviting people over, it's our responsibility to provide. It's not the same to me as if we were just having a picnic for the whole family, in which case I would be very comfortable asking people to bring things. Just his aunts/uncles/cousins and kids etc.. total almost 75 people. I am only going to invite my sister and BIL and my parents so that's only an additional 4 people on top of his family. WWYD? I am not sure I can physically make everything for that many people PLUS make the birthday cakes, clean the house and work that whole week. But, I just can't bring myself to ask anyone from his family to make something. Should I just get over it and tell them to bring something?? The 2 aunts he is really close to along with a few of his cousins we are close to have all said 'let me know what to bring' but I still feel wrong asking them! WWYD?
Sorry it's so long... I just don't want to be tacky!

Re: I need help!
I think what you wrote sounds great. Very positive.
As for bringing dishes, I'm with you. I wouldn't ask people to bring anything. However, if they offer (which they will) you can give them some ideas of what might be a good contribution. It's perfectly fine to accept their offers to help.
If you are preparing for 75, keep it simple! You can choose something to make ahead of time & just heat up that day, like lasagna & salad, and order cupcakes from Kroger so you don't even have to worry about plates or forks. GL!
I like what you wrote and can't think of anything else you need to say.
As for asking people to bring food, that completely depends on the dynamic of his family. In my family every single celebration is a potluck. It has been since before I was born. Who ever hosts the party has to tell everyone what to bring otherwise they get numerous phone calls and emails from everyone wanting to know what to bring so that there aren't duplicates.
However, if it isn't normal for his family to all pitch in then I think it would be weird to ask people to bring food with them.