Dear N.
I'm sure you've heard this before - life isn't fair. It is a series of trials and tribulations, but we can be of good cheer because the Lord has overcome this world! We go through these troubles to learn and grow - learn to love unconditionally, and grow into the image of Christ.
Although you didn't mention Jesus Christ or a relationship with Him, He is the answer - for your husband, your daughters and yourself. Except, wait, you said soon-to-be step daughter which means you are not yet married to this man. That doesn't change that Jesus is the answer, you will just have a little bit more to repent of and He is faithful and just to forgive us of ALL our transgressions.
Frankly, I don't know how non-believers get through one single day without Him. He brings such peace in the midst of "episodes". He watches over the little ones and appoints each an guardian angel for extra protection. He's always there to listen to our prayers and "loves with a love that is more than a love" to quote a famous poet.
His love is never conditional on how we act or what we do - good or bad. He simply always loves. I will pray for your fellow and for your girls and for you.
Father God, I lift up this young mother so much in love with the father of these two little girls who is having a difficult time with bad memories. Lord, I thank You for Your unconditional love and for having me read her request so that I could pray and ask You to heal his mind. Father, give him Your sweet peace that passes all understanding and help him to live in the day and look forward to his bright future in relationship with You.
Holy Spirit, teach him how to lay those bad memories down and replace them with good ones. Reveal to him the Truth and the Way so that he can come and be refreshed and know that ALL things - not just some - work together for the good of those who love You and are called according to Your purpose. Then help him be a godly father in his household.
Give this young mother peace, also, Lord and help her to be full of Your joy which can be her strength to walk through any valley. Help her to rejoice and give thanks for these troubles knowing that You are working to make her into the image of Christ Jesus. Send godly older women to teach and help her to learn Your ways.
And last, Father, be with these little girls. Guide and direct them and keep them always in your loving embrace. May their days be filled with love and laughter so that when the sun is covered by clouds and when it rains, the can be full of hope that there will again be a bright warm day. Give them Your blessed assurance that they will know You and spend their eternity with You.
Thank You, Lord, for loving us so and for Your thoughts turning to our days. It is so awesome that You have made a Way for us to come and be Your children through Your beloved son Jesus and His sacrifice. Thank You for answering my prayers, too. You are so good ALL the time and I love You and give You all the praise and glory because You are worthy. Amen
Sorry, N. that I didn't have specific information from knowing someone with PTSD, but I know that my reading and responding to your post was divinely arranged by a Father who loves you. I pray it helps.
Hugs and blessings
Grami
p.s. marry this wonderful man asap : )