"When his daughter was released from hospital she wasn't letting him feed her, hold her" when a baby is born the way this one was with those complications they can have issues with feeding, reflux and breathing and even occasionally heart issues. There may well have been very specific safe ways that the baby needed to be held and fed which the mother will have been shown in hospital. In addition it's very natural for a mother to feel over protective following a traumatic birth, even with a "normal" birth with hormones, sleep deprivation etc overprotectiveness can kick in - that's completely natural and even healthy.
Remember mum and baby have only been home 4 WEEKS, mum is still getting to grips with caring for baby herself and she has the added issue that I've heard from many teen mums and read on here that young mums can be under much greater scrutiny/criticism from everyone from their own families to health care professionals and even complete strangers - you're guilty of this yourself!
She will have had it drummed into her the right way to do things for this baby while caring for her in scbu, where everyone is hyper vigilant!
I was 28 when I had dd, she was my rainbow after 2 mc losing 3 babies, the pregnancy had been medically very dodgy and I was closely monitored as being "high risk" then the birth was long and slow and then went very wrong at the end very quickly and frighteningly so! Dd and I both nearly died for different, rare unpredictable before the birth reasons, ending in an emergency c-section.
The protectiveness I felt was overwhelming. At one point while I was with dd in scbu dd had to have an emergency procedure which short term was EXTREMELY painful and they'd no time to administer any anaesthesia, the scream I will NEVER forget, my then husband literally had to carry me 2 days post cs out of the room to stop me dragging the hcps off dd. Even though logically I knew they needed to do what they were doing - it's a visceral, instinctual reaction that really DOESN'T take account of logic.
I was SO apologetic and ashamed after but the hcps were lovely and told me it was a perfectly normal reaction that they were used to and to think no more of it.
Once home dd had some wounds due to necessary procedures and I really wasn't at all comfortable with her dad bathing her initially, as I'd been instructed to do so in a very specific way and shown how in hospital which her dad hadn't.
But he understood and helped in other ways until I felt ready for him to do that task.
So your friend needs to be PATIENT it is very early days still, the mum AND the baby are still very much adjusting to baby being outside her body (tell him to google "4th trimester" also)
I very much agree with the advice not to pester the mum, politely and briefly ask re visiting arrangements where necessary but give her space.
"He sends me screen shots of him messaging calmly and in return she would be hostile for no reason." Bear in mind he could easily edit what he's showing you. Don't assume you're getting correct info.