Is there anything specific about living in heaven for eternity that makes her sick? I understand that many times our concepts and imageries of heaven might turn a person off from wanting to be there. I would get bored in a place which has streets of gold and so on. The important thing is that we are going to be with God and enjoy his presence forever.
That is the beautiful hope of the afterlife. To be with God. It is the relational aspect that makes heaven what it is. That presence of God which we feel so strongly in our hearts in this world will be manifested completely on the other side of eternity. That is a hope worth holding on to. That is an endeavour worth striving towards. I think if you emphasise the relational aspect of the Kingdom of God and the beauty of the harmony in relationships that God will restore for us, it could comfort your wife.
Praying for you Samuel. God bless you.