So far it has only made his insomnia worse, but we have been told it needs a time to kick in. I have done some reading about zoloft and am a bit worried about it's side effects.
Antidepressants work by promoting the growth of new brain cells
in the two hippocampal regions of the brain to replace cells that have either been killed by chronic stress hormone exposure, or prevented from budding and growing, so their effect isn't immediate. It typically takes an antidepressant 3-12 weeks to kick-in.
SSRIs can trigger a range of side-effects, but mostly these only occur in the first few weeks they are taken and they usually diminish by the time the med begins to work though some such as sexual dysfunction may linger.
One common SSRI side-effect is insomnia. It often is only temporary, but if it continues for more than a few days the best treatment is small doses of the very sedating antidepressant trazodone. At the doses usually prescribed for insomnia, 25-50mg, it exhibits no antidepressant properties acting only as a powerful antihistamine so it won't affect the Zoloft. Benadryl may also be worth trying.
Are there any safer non-medication strategies he could try?
Zoloft is actually a very safe med. While the side-effects can be unpleasant they don't cause any physical harm. and there are health benefits in taking SSRIs. For example, they slightly reduce blood coagulation which tends to lower the risk of heart attacks and ischemic stroke.
The only treatment that has comparable rates of effectiveness to meds are the cognitive and/or behavioral and mindfulness therapies. Both exercise and Omega-3 fatty acids/fish oil have been shown to also promoted hippocampal brain cells growth and may ease mild anxiety, however, they are unlikely to ease severe anxiety.