A friend sold some investment real property this year and had a large long term capital gain. He invested the proceeds in the market and the values are down. If he sells the investments now he will have some short term capital losses. Can he use the STCL to offset the LTCG? He also paid estimated taxes on the LTCG so if he can use the STCL to offset the LTCG, he should be able to get some relief from the estimated taxes he paid earlier this year... correct?