Have Head Injury. Titanium Plates Planted. For Flap Rotation Plates Were Removed. Gap In Skull. Fill Up By Itself?

hi doctor , my son is 10 yrs old . one year back he fell in a 70 feet well .. he sustained head injury ...he went thru a neuro surgery where titanium plates were planted in his head to hold the broken bone pieces . un fortunately the skin on the top gave way . he had to be put thru another surgery in which a flap rotation was done, also the plates implantd earlier were removed,... nw he has a gap in his skull measuring 6cm by 4 cm. my question to u is .....

do such gaps fill up on his own....?

do we need to get it covered up...?

thnk you
Chitra