My pal's wife is very poorly and got few days to live. Lots of family from UK are over to spend time with her

How many folk can attend the funeral ?

My main question is about the wake. We have a lovely big place here and would love to offer it for the family after the funeral, but not sure of the rules. Google didn't help.

Will I be in trouble if I have all the family and friends here ?

Spain are much tougher at enforcing rules than in UK. No idea what rules apply in Lanzarote. I would ask for advice at your local town hall / local police office.