You can befriend an adult child the same way that you would make friends with any other adult. You need to find a way to spend time with him or her. Go out for breakfast or a cup of coffee. You can offer to help with various projects that might come up in their home, or invite them over to help with a project of your own that they might enjoy.
Everyone wants friends. If that friend is your parent, it has additional benefits. You already have a life-long relationship to build upon. You also already have many friends and acquaintances in common in your own extended family. Even if you were not buddies while you were raising the child, most of this is forgiven if an offer of friendship is extended from the parent to the child.
Do not interfere in your child's adult life. Give him or her the same space that you would give any other friend. This may be your child, but respect and room is still the order of the day. Be careful not to be too judgmental in giving advice or discussing decisions and lifestyles. You would do this for a stranger. It should be easier to do for someone you know and love.
Express your affection for your child. Do not be afraid of the words: "I love you." This goes a long way toward breaking down barriers when it is sincere. Let the child know that you are available if he or she has needs arise. If the child knows that you are there, it will help them cope even if you are never called on for help.
Treat your grandchildren nicely. Parents like people who like their kids. Small token gifts and appropriate hugs for the grandkids will bring down old barriers faster than any apology could ever do. Help run a few errands for the children to help remove a little of the parenting pressure from their shoulders.
Work on learning to like some of the things that they like. Play some table games with them, or take up a similar hobby. Watch for small things that they like when you are shopping a buy them a surprise once in a while. They liked it when they were little. They will still like it as adults. Remember birthdays and anniversaries. They may not remember yours, but it will mean a lot that you remember theirs.
