Hi thank you for your question. Please remember to RATE my answer OK SERVICE, GOOD SERVICE OR EXCELLENT SERVICE so I can get credited for my time.
You question seems essentially two fold. First I will deal will the issue of your husband being allowed to settle in the UK.
1. Your husband will need to apply for a Spouse Visa from where he is currently residing. Before a Spouse Visa can be granted you must ensure that you have secure employment in the UK which pays £18,600 pounds a year gross. If you do not then the other option would be if you or your husband have savings of £65,000.00.
Your husband will be give a 5 year spouse visa if your application is successful he will obtain firstly 33 months visa then if your relationship is still subsisting and you still meet the income threshold of £18,600 (his income would also be taken into account if he is employed in the UK), he will further need to make an application for another 33 months. Once he has been in the UK for 5 years he will then be able to apply for indefinite leave to remain.
The list of requirements is and the form can be found at the following link:
2. Regarding the issue of your in laws, if they are residing with you as visitors they will not be entitled to any medical care via the NHS, they must pay for all medical visits and any medicine's that are prescribed to them.
I hope this answers your question, if so, kindly rate my answer positively so I can get credited for my time.