Should I be included in my grandsons mortgage?

Depends if his income is high enough to buy something suitable for you and his family.

I would speak with a local Lender, they can often tell you which way would be more beneficial. And as the other answer indicates, there may be some things to consider.

That would be a better questions for a mortgage lender. They would be able to tell you how much of a house he qualifies to buy, and that can determine whether or not he should add you to the loan. Just know, there is a little bit of risk because both of you will be liable for making the payments, even if you no longer live together a couple years down the road.