Hi there,
Here the word 'engaged' is not in the passive. It looks as if it is in the passive because it looks like the same structure. However, the word 'engaged in' is playing the role of an adjective in describing a state. Have a look at these three sentences:
'He is engaged in many activities' - acts as an adjective describing the state of being engaged in something.
'He is engaging in many activities' - here 'engaging' is used as a verb describing the action of engaging in an activity.
'He has engaged in many activities' - acts as a verb in the present perfect, referring to the action of engaging in many activities
A similar example can be seen with 'closed':
'The shop is closed' - adjective describing the state of the shop
'We are closing the shop' - verb describing the action of closing the shop
'Involved in' is also similar to 'engaged in':
'We are involved in many projects'
Hope this helps!