Words fail to express how sorry we/I feel for your loss. (Insert the Name) will be definitely missed by us/me.
All these years we did value his/her (speak of some of the features/action of him/her). We/I / sure to miss his (describe what are the things you are going to miss). We/I will always cherish (Insert the Name)’s sweet memories deep inside our/my heart/hearts (say the reasons why you think he will always be in your heart).
We/I know his qualities (Mention one or two qualities of him which you found very amazing) were always loved by all. He will be an inspiration for us/me (Tell briefly how do you feel he will inspire you, both personally and professionally).