Child from previous marriage - Double question about visas & healthcare

Hey everyone - hopefully someone will be able to help me out with my questions! I am a US citizen and I have a child from a previous marriage. I am marrying a UK citizen and will be settling in England. First of all, does anyone know which visa I have to apply for for my son? I know I need a spouse visa, but I'm confused about my little one. Also, how long does it usually take from the date of application to get a spouse visa approved?

Second, will both me and my son be covered by NHS? Does my son have to be legally adopted by his step-father, or will he be covered by default when my finace and I get hitched? Any info would be greatly appreciated!

You would need a VAF2 as a dependent child of someone intending to settle in the UK (assuming he is under 18 years of age).

You will also need proof that your former husband will allow you to take the child to the UK and/or have a court order that you have full custody of the child.

NHS is available to anyone settled in the UK, this would include both you and your son from the time you arrive.