I was just pricing cloth tablecloths on line, just basic cloth vs vinyl and I was surprised that the prices were considerably higher than they were about a decade ago the last time I bought them.
I've made a couple of embroidered tablecloths and those tablecloths are not the greatest quality preprinted and those kits are expensive.
The crocheted lace tablecloths I've seen are heirlooms made by family for family and passed down.
You might want to research patterns and see how much thread you are looking at and then get an idea of what it will cost you just for the supplies alone. This is a HUGE undertaking.
Realistically even if they were willing to have a thicker tablecloth it can't be acrylic yarn because you can't risk someone putting something hot on it and having it melt. So it's going to have to be cotton or something else that won't melt?
I'm not sure if this was a commissioned project or a gift request but it is a huge request either way. My experience is that people asking don't always understand what they are asking. I had a request over Christmas that I turned down because the person asking had no clue that it wasn't a "simple" request. In that person's mind it seemed easy enough because I'd made other items however this one was not something I'd have enjoyed making and I said no.