It seems that the bone is wide enough (8 mm, Fig.2 (CT coronal section) (P: palatal)) to hold a 4 mm implant (Fig.3 (axial section)). Since bone density is low at the coronal (100-200 units) and middle (50-100 units) segments (Fig.2), bone condensation will be beneficial.
Xin Wei, DDS, PhD, MS 1st edition 02/18/2017, last revision 09/05/2019