At minimum, all critically ill non-bleeding patients with DIC should receive prophylactic anticoagulation for venous thromboembolism.
Regarding therapeutic doses of heparin, the 2013 ISTH harmonization guideline states:
Anticoagulant treatment may be a rational approach based on the notion that DIC is characterized by extensive activation of coagulation. Although experimental studies have shown that heparin can at least partly inhibit the activation of coagulation in DIC, there are no RCTs demonstrating that the use of heparin in patients with DIC results in an improvement in clinically relevant outcomes... therapeutic doses of heparin should be considered in cases of DIC where thrombosis predominates (low quality evidence). The use of low molecular weight heparin (LMWH) is preferred to the use of unfractionated heparin (UFH) in these cases (low quality evidence).