FIL in NH. He fell & was taken to ER. Wife was called but she did not call us. Can we ask them to call us or will they only call spouse?

Not fair to make son POA when a spouse is involved.

The best you can do is ask Dad to put u on any HIPPA paperwork. The wife cannot give permission for son to be on Dads HIPPA papers.

Most medical establishments prefer to have one point of contact. You could ask both the NH and the local hospital to put your husband’s name on FIL chart to be called for emergencies but with HIPPA rules etc they may not be willing to add extra names without permission from FIL or his wife.
This is one of those things that should be worked out well in advance. You don’t mention dementia on the profile. If FIL is still able you could ask him to sign a release and/or make his son his POA. I hope he is better soon.